Tech Report: A Look At The EDRAM On Valhalla

We brought you our inside the 360 slim feature just over a week ago, revealing the internal layout of the console, and the all important details surrounding the chip and die shrinks contained within. However, one piece of the puzzle was missing – both the size and exact whereabouts of the EDRAM in the CPU/GPU package. This is something which is of particular interest seeing as this piece of silicon has always been behind in terms of process node changes, and has yet to be intergrated into the same die as the GPU.

This still seems to be the case - as you will see in the image of the console’s motherboard below – that the EDRAM is a separate entity from both the CPU/GPU combo, which now appears to be housed on a single die.


So, both the GPU and CPU are firmly on a single die, and the EDRAM is once again separate, all of which is housed on a single package, codenamed Valhalla. The CPU/GPU is now on a 45nm process node, although the EDRAM looks to be noticeably larger. The overall die size is some 34% smaller than the Jasper chipset’s CPU and GPU combined, inc EDRAM. And is 53% smaller than the ones used in the first 360 chipsets. For reference the Jasper chipset featured both the CPU and GPU at 65nm, whilst the original 360 featured 90nm versions of both chips.

From the above image it doesn’t look like the EDRAM has been fabbed at 45nm – it’s far too large in size for that. Instead all signs point to it being around 55nm or 65nm as speculated in our original article from a couple of months back. Interestingly, this is opposite to what the latest pieces of scattered information were saying in our later article – in which a 45nm EDRAM was hotly expected to be included.

Why the difference in die size compared to the other chips then? Well, the EDRAM itself has always been behind on process reductions, with complications in shrinking the chip being the main reason behind such slow comparative progress being made. Cost is also another factor. It could be that it is simply too expensive to economically reduce the EDRAM in size whilst obtaining optimal yields during production (a certain number of chips produced are unusable). Plus, the slower progress of reliable die shrinks to the EDRAM could have also held back development of the Valhalla CPU/GPU combination, with the complex integration of the EDRAM at a different size posing unnecessary problems and expenditure.

Integrating all three chips (CPU, GPU and EDRAM) would take the cooperation of ATI, NEC and IBM in order to make it happen given the increased complexity required for such a design. The cost of which would have been larger than simply producing three separate chips, or in this case two on one package. Another issue is getting the design and final production grade silicon ready on time, and given the increased complexity it is unlikely that this was ever going to happen. Effectively, all things considered, the cost/benefit ratio to having not only die shrinks, but also complete integration of all three chips on one die was perhaps too poor for consideration.

That’s not to say that later on down the line the EDRAM won’t be included in another internal revision of the 360, because it is very likely that Microsoft are working to do exactly that at some point in the future. It is possible for this to happen now, just not quite being the cost saving measure they are after at this point in time. Maybe with the next, and possibly last revision to the hardware, we will find that all three chips will have been completely integrated into a single die, rather than a single package. At that point, we expect that the EDRAM along with the now combined CPU/GPU will all be produced on the same process node.

With the current Xbox 360 S (slim) we have here what is clearly the best price/performance ratio available at this point in time with regards to heat reduction, and overall saving in silicon. Whatever changes we (and many others) might speculate, there is no doubt that Microsoft have done their very best in producing the most efficient, and cost effective version of the 360 to date. It is also the quietest and most solidly built too, which is not something you can really say about the console before the Slim’s arrival.

Tech Report: Inside The Xbox 360 Slim

Earlier on in the week at E3 in Los Angeles Microsoft unveiled the brand new slim version of the Xbox 360, finally ending rumours of a new outer casing design and internal component revisions. We first reported on the 360 slim way back in march when photos of its motherboard were leaked onto the internet, showcasing what looked like a combined CPU/GPU on a single chip or die, and boasting a more efficient single fan cooling system. Now, with the console starting to filter into homes and into the hands of various tech-savvy enthusiasts, we can finally take a look under the hood of the machine and its internals.

Those of you expecting any last minute revelations are likely to be disappointed, as much of what we said back in our original 360 slim report was pretty much 100% correct. The use of a combined CPU/GPU and EDRAM, internal fitting hard drive, optical output, and external power supply are all correct and present, as is too the lack of any memory card slots or ability to use the old 360 hard drives on the new unit.


Looking at the final retail console’s motherboard (pics of which are quickly circulating around online) we can see that this latest revision of the 360 console uses the long-time rumoured Valhalla chipset, which consists of a CPU, GPU, and EDRAM all on one package. I say package as each of the chips are single entities housed all on one die, with the CPU and GPU produced on a 45nm process node.

As for the EDRAM, well it looks like that might also be produced at 45nm like the other two chips, although this isn’t confirmed. Last we heard TSMC were having trouble shrinking down the EDRAM on a 45nm process so we surmised that it might have to be done on something like 55nm. This now doesn’t seem to be the case, with sources pointing to the chip being finally fabbed at 45nm, which also goes hand in hand with reports that the Valhalla chipset as a whole is being manufactured at the Global Foundries owned Chartered Semiconductor.

Anyhow, the brand new single die design means that the chip runs a lot cooler than previous versions, which are larger and more power hungry. The advantage is that the new slim can be cooled with just one fan, and an efficient heat dissipation system build around that design. To that end the fan covering the CPU/GPU/EDRAM package is housed directly below the vents situated on the top of the outer casing, along with the actual chip package itself. The fan draws in cool air from the top of the console and then blows out heated air through the sides, dissipating the heat far more efficiently than previous models were able to do.

Other than the brand new combo chip package, the motherboard has also seen a complete re-design looking a lot more streamlined than before. Much of the excess fat has been cut, and components that were no longer needed have been cut away leaving a less cluttered design behind. Again, less stuff needed to be powered equals less overall heat, so there are less likely to be any issues of additional components creating heating issues in such an enclosed pace.

One thing that does appear to be the same as in the previous Jasper model 360, is the use of those 1 Gbit Samsung DDR3 RAM chips for the system’s unified memory. With a complete revision to the CPU and GPU, along with a streamlined motherboard, one might have also expected some kind of revised memory system as well. That doesn’t appear to be the case, and although two GDDR5 sticks would be preferable, Microsoft would then have needed to replace the existing memory controller as well. Plus at this point the use of GDDR5 isn’t at all feasible with low production numbers, and the actual cost saving using the new chips might not actually be that much cheaper, if at all at present.

Perhaps just a little too much work for minimal results, especially when it really isn’t needed as the new unit already draws far less power than before. Plus, it’s likely that MS will be making a large cost saving once these fabs ramp up production of the new components found inside the console.


Moving on, unlike previously speculated the 360 slim doesn’t have a built-in internal hard drive. Instead the HDD whilst technically being internal, is also completely removable and is housed inside a custom casing created by MS, which then lives inside the back of the machine. The new HDD being used is a Hitachi HTS545025B9SA00 1.5Gbps SATA hard drive, running at a speed of 5400RPM with an 8MB buffer.

Seeing as the new HDD connects via a standard SATA port it might be possible to hook up larger capacity drives to the console, either by swapping out the hard drive from inside the MS casing, or by simply connecting one externally via the SATA port. So far no one has tried this just yet, but the modding potential is definitely there for those of you out there who are skilled enough to do so.

Once again the system’s power supply is external. As we found no evidence of it being internal in our report on the motherboard back in march, that isn’t really so surprising, and given the cooling problems of previous units probably for the best. Thankfully though the PSU is much smaller than before, and is more stylish looking too – smooth curves and all. Well, it is as stylish as a PSU can be.


Lastly, and we though this was worth a recap over our initial reveal of the unit, is the inclusion of an input for connectivity with Kinect situated above the Ethernet port. This port both powers the Kinect device along with interfacing it with the 360 console for data transfer, and processing on the 360’s end. Users of any older model 360 will have run two separate cables in order to use the Kinect; One which plugs into a USB port on the 360 to interface with the unit, and another from the Kinect going into the plug socket in order to power the device.

Clear signs point to a 360 + Kinect bundle at some point, and the motherboard and overall design for the slim console shows that this was factored into it.

Overall, Microsoft has done well in creating a streamlined and power efficient revision of the 360 console. What we have here is a rather good combination of chip/die shrinks with improved cooling and heat dissipation, meaning we should see far less in the way of hardware failures, and of course high-levels of operating noise. It’s a nicely engineered piece of kit, both internally and externally, that finally presents the format as a premium product very much in same vein as the PS3.

The brand new 360 Slim hits retailers on July 16th in the UK, with most retailers now taking preorders for the console. It is priced at £199.99, the same as the current Elite model it replaces, which along with the Arcade SKU will see a price drop the same day the slim is released.

IQGamer will of course be bringing you our hands-on with the new unit as soon as possible, hopefully right around the time of launch, or very soon after.

Could This Be 360 Slim?

There have been rumours about an eventual slim line version of the 360 for a few years now, with various sources and unsubstantiated reports sighting plans for an all-in-one CPU, GPU and EDRAM chip, coupled together in one massive internal revision of the 360 console. That revision was allegedly known as Valhalla, which would see both the main processing components of the 360, along with the EDRAM, shrunk down into one power-efficient little chip, bringing down the cost of production, and allowing for a complete design makeover.

At the time, it was impossible to expect such a revision to appear for at least a couple of years, given the slow and struggling process of being able to shrink down the EDRAM in line with both the CPU and GPU inside Microsoft’s console. So much so, that only last year were the fabrication plants at TSMC were able to significantly reduce the size of the 360’s GPU, resulting in the much more reliable ‘Jasper’ revision of the hardware.

Yesterday however, two leaked photos seemed to show that those initial problems have in fact been alleviated, now allowing a combined CPU, GPU and EDRAM on a single chip, or at least on one single die containing all three separate chips, albeit much smaller in size than before. It also shows what looks like a complete re-engineering of the 360 motherboard into a much more compact form, at least one third smaller than the current design, and a glimpse into the potential release of a slim 360 console.


The two images in question were released on a Chinese tech forum, A9VG, and shows what looks like a genuine reworking of the 360 motherboard, while also revealing various other changes inherent in the basic design of the new console. The first photo above, shows the actual shape of the motherboard it self, demonstrating the new small size, at the same time teasing us with an image of a smaller combined chip underneath a stock Coolermaster cooling fan.

From what we can see, it’s pretty obvious to us, that use of an off the shelf cooling fan isn’t likely to be part of the final retail unit of this 360 slim. Instead all signs point to these photos being of a test unit, still under development and in the last stages of trialing, before being cleared for a final production to start. However what’s interesting is that the second photo clearly shows us a single CPU and GPU package on what could be a single chip, along with changes to the motherboard showing perhaps what kind of hard drive they will be using for the unit, in addition to changes with regards to the type of audio outputs available on the machine in this latest model.


This second shot shows us all of the motherboard and its features in clear view, most noticeably confirming that the CPU, GPU and EDRAM sits together on either a single chip, or more likely a single die, with the each of the three chips being separate entities integrated onto it. My reasoning behind this is that integration of the EDRAM and GPU into a single chip would actually require a major redesign in order to fit into the shader core, whilst also having to be produced on the same process node. Basically it would have to be fabricated at the same size as the main GPU, something that is still a problem at the TSMC from what I’ve been hearing.

Another thing, is that due to the photographer’s lack of removing the heat spreader, we don’t really know for sure just what is lurking underneath, or what process node the chip is on. I’m pretty sure it would have to be at least 45nm, but then it would mean that the CPU, GPU and EDRAM are definitely still separate chips housed in one die, rather than a single chip. It’s highly unlikely that the EDRAM could be processed at a 45nm; instead more along the lines of 55nm, making this part separate at least from the CPU and GPU.

Interestingly the motherboard looks to contain parts required for additional features to be present on the slim 360. Now, these are pretty much a reworking on the things which the current machine already has, just done in a different way. The first thing that comes to mind is the extra SATA connector available for use on the board, bringing the count up to two. On the current 360 the board only has a single connector, used for the DVD Rom drive, whereas here on the slim, an inclusion of a second seems to hint at an internal hard drive storage solution, or at least a new type of external connecting HDD.

An internal drive is unlikely, as it would prevent an upgrade path for arcade users, whilst also preventing Microsoft from selling larger hard drives later on down the line. However, they could in theory break free, and make a fresh start with the slim, whilst still producing HDDs for existing 360 owners. In fact, that is probably the most obvious choice, as a clean break is the only way for them to achieve a cost effect new hardware design.

Also there’s no sign of the mounting holes used to fix the existing DVD drive into the unit, and at any rate, it would not fit into the new slim design, leading me to believe that either MS are planning to give us a shiny slot loading type drive, or are simply moving its position around a bit. Perhaps they will use some kind of top-loading system for the slim, although more likely is another version of the current slot-loading drive found in the fat 360s.

Memory card readers have also been cut down to one unit now, and there is no sign of any inbuilt wireless adaptor, which is disappointing. I guess MS are making too much of a killing by selling the existing Wireless N adaptor at 60 quid, and would rather continue with their lucrative margin on accessories. However, they have seen fit to at last include an optical output on the back of the new unit, meaning the end of buying the overpriced audio dongle for surround sound when using a HDMI cable without an HDMI compatible amplifier.

From what we gather, the power supply seems to be another external jobbie, unlike the tightly integrated PSU of the slim PS3, which although mildly disappointing, at least allows the machine to be potentially much smaller than the current design. In that respect we expect the overall size of this new 360 to be smaller and more representative of its unofficial ‘slim’ moniker than with the latest PS3. You could say that from the motherboard photos it could well end up looking a little bit like the Dreamcast, just with a stylish slot loading drive instead of an outdated top-loader design.

That’s pretty much all we know right now, not being able to shed anymore light on that interesting single chip/die CPU, GPU and EDRAM combination, or to ascertain whether this latest revision of the 360 hardware is in fact a slim console, or just another revision, albeit a massively more drastic one.

All signs do point to something major happening though, with Microsoft advertising for a Motherboard Design Engineer for the Xbox console, who is being described as being responsible for "aggressive cost reduction of the console throughout the life of the product”, and at the same time, past candid statements from company execs, which detailed plans for a brand new version of the 360 console due to release at the same time as Natal.

As per usual Microsoft declined to talk about the matter, issuing the same “we don't comment on rumour and speculation” line heard many times before, but this isn’t the first time such unofficial leaked information has provided the solid background for hardware confirmation. PS3 slim was revealed in much the same way many months before it was announced and released.

Ultimately we don’t know whether this is going to be a 360 slim for sure, though all signs do point that way, and in any case, Microsoft like Sony, wouldn’t want to reveal anything too soon as not to disrupt current sales of the existing 360 console, especially many months before the new machine is ready to go.

Either way, it won’t be long before we find out even more details, and we're willing to bet that unofficial leaks will be the leading source of information long before any official announcement takes place.