Published byAnand Lal Shimpi on 2010-06-21 Category: Xbox 360 | Page Views: 6465
This is the latest revision of the Xbox 360, commonly referred to as the Xbox 360 Slim thanks to its shrinking in virtually all dimensions compared to the previous white box:
The internals are mostly new, featuring for the first time a single chip with CPU, GPU and eDRAM. Prior to this motherboard revision the Xbox 360 motherboard had two discrete packages, one with the CPU and one with the GPU + eDRAM.
The old Xbox 360 had eDRAM and GPU - Xenos on a single package (right), plus a separate chip for the CPU - Xenon (left)
For those of you who don't remember, ATI originally designed the Xbox 360's GPU and called it Xenos. The GPU was the first we ever looked at that used a unified shading architecture, so there were no dedicated pixel or vertex units. The core was made up of 48 shader processors and each SP could work on a vect4 plus a scalar op in parallel. These days we'd probably call it a GPU with 240 cores, although it's a bit dated from a functionality standpoint. The GPU runs at 500MHz and is also home to the memory controller.
The DVD Drive & Motherboard
I pulled all 12 screws out but left the four heatsink screws in place since I wanted access to the motherboard. With all four removed I could pull off the bottom cover leaving me with this:
The CPU, codenamed Xenon, implemented three in-order PowerPC cores with SMT support - meaning the whole chip could work on six threads at the same time. The design was ahead of its time but given its 90nm manufacturing process it only had 1MB of L2 cache to share among all three cores. These days it isn't really considered the ideal approach to a many-core CPU. Private L2 caches with a large shared L3 cache is preferred for scaling beyond two cores.
Leading up to Jasper, each die was shrunk independently with each Xbox iteration. The table below shows us how:
Xbox 360 Revision
CPU
GPU
eDRAM
Xenon/Zephyr
90nm
90nm
90nm
Falcon/Opus
65nm
80nm
80nm
Jasper
65nm
65nm
80nm
With the new Xbox 360 (codenamed Valhalla), at least two, possibly all three of the die are combined and placed on a single package:
Bringing it all onto (presumably) a single die makes cooling much simpler as now there’s only one heatsink and one fan for all of the major heat generating components in the unit. This level of integration is made possible only by the not-so-magic of Moore’s Law. At 40nm it shouldn’t be a problem to bring all of those components onto a single reasonably sized die, which in turn reduces Microsoft’s manufacturing costs. It’s not totally clear whether Microsoft is building these chips on a 40nm, 45nm or 55nm node. The 40nm approach would make the most sense but TSMC is very capacity constrained at this point so it would be a slow ramp before all Xboxes got the Valhalla treatment. Update: Apparently 45nm is the magic number. The new CGPU is rumored to be made at Chartered Semiconductor, now under the ownership of Global Foundries.
The uncertainty is because of a pesky heat spreader. While previous Xbox 360 CPU/GPUs were visible to the naked eye once you popped the heatsink off, the Valhalla design has a heat spreader covering the Xbox CGPU (Microsoft’s term, not mine). Unwilling to potentially kill yet another Xbox 360, I’ve left my heat spreader intact for the purposes of this article.
Much Prettier than the Original
Microsoft took a page from Sony’s playbook and outfitted the new Xbox 360 with all touch sensitive buttons. The eject button is much smaller but extremely sensitive, not to mention you get a loud beep whenever you hit it. There are no issues with knowing whether or not you hit the eject button.
The power button is pretty much the same way, a light tap will toggle it and send you on your way. The green ring of light apparently doesn’t turn red anymore (it only flashes green when there’s a problem? engineering meet marketing). On the bright side like Jasper before it, there is no reason the new Xbox 360 should have the same RRoD problems as the older models. As you’ll see from the dissection not only is it a new chip fabbed on a new process, but it’s apparently cool enough to require much less force exerted on it by the heatsink clamp.
The exterior is a glossy black plastic. It looks great but picks up fingerprints and smudges like the dickins. A definite problem for those of you who like to cart your 360s around.
The Xbox 360 memory units are no longer supported but there are two USB ports up front that will accept USB drives as data storage.
Around back you get an optical audio out, Xbox 360 AV connector, HDMI output, three more USB ports, Ethernet port and input for Microsoft’s Kinect peripheral due out later this year.
There’s 802.11n support integrated into the new Xbox 360. If you open up the case you’ll see a USB 802.11n adapter plugged into an internal USB port. This also makes me wonder if we’ll see a cheap version of the new 360 without WiFi support.
The hard drive is still a 2.5” model but now it’s tucked away at the bottom of the system (standing up) in a much smaller case. To get to it just pull back on a couple of the fins which will let you remove a part of the cover:
Yanking on the black ribbon (it takes a bit of pulling) will pull out the hard drive itself. Microsoft appears to have sealed this drive up pretty well. I’m not sure there’s a way to remove the physical drive without irreversibly breaking open the case. I had other ways of figuring out what was inside so I didn’t bother taking this one any further.
The new hard drive is a Hitachi HTS545025B9SA00 1.5Gbps SATA hard drive. It spins at 5400RPM and has an 8MB buffer. If you were hoping for a 7200 RPM drive, you’re out of luck.
Power Consumption: 50% of the Original Xbox 360, and Quieter
Moore’s Law is good for any of three things: 1) increasing performance, 2) adding features, 3) reducing power. Consoles have the benefit of not having to worry about improving performance or adding features over time. There are no changing API specs and games are always designed to the same hardware performance level. This leaves us with improvements in power consumption (and Microsoft’s profitability).
The new Xbox 360 power connector (right). It's slim.
The new power brick isn’t compatible with the old Xbox 360s. At 135W it isn’t enough to power even the Jasper Xbox 360 and thus you get a new power connector. It’s much lighter than the old unit and a bit smaller, but still larger than anything you’d get with a notebook for obvious reasons.
New power brick (left) vs Old power brick (right)
Given my plethora of Xbox 360s I happen to have a good amount of historical data on power consumption for all of the major revisions, I’ve added the relevant Valhalla numbers below.
Power Consumption Comparison
Xbox 360 Revision
System Off
Idle
Halo 3
Rockband 2
Gears of War 2
Red Dead Redemption
Xbox 360 Slim (Valhalla)
0.6W
70.4W
87.0W
82.7W
88.0W
90.4W
Xbox 360 Late 2008 - 2010 (Jasper)
2.0W
93.7W
105.9W
101.0W
105.9W
109.3W
Xbox 360 Late 2007 - 2008 (Falcon)
2.8W
101.4W
121.2W
112.8W
121.5W
Xbox 360 2005 - 2007 (Xenon)
2.3W
155.7W
177.8W
167.7W
177.1W
The biggest improvement is actually when the system is totally off. The new Xbox 360 slim pulled 0.6W compared to over 2W for the older 360s while doing nothing more than being plugged in. Idle power is roughly 75% of what it was with the Jasper Xbox 360 and load power is around 80 - 83% of what we saw with the previous generation. Note that the new Xbox 360 consumes less than half the power of the original 360!
Idle power consumption is actually not very impressive for a 40nm Xbox 360 if that's indeed what we're looking at. A modern day Core i5 system with an efficient power supply will idle at under 70W with a beefy discrete graphics card. While this is a significant drop compared to previous Xbox iterations, it's not impressive as a computing device.
The savings are tangible however and also result in a cooler, quieter system. The CPU and GPU are now cooled by a single, larger fan that keeps idle noise down to a minimum. I measured noise levels between Valhalla and Jasper at 2” away from the chassis and came up with the numbers below:
Sound Comparison
Xbox 360 Slim (Valhalla)
Xbox 360 Late 2008 - 2010 (Jasper)
Idle
45 dB(A)
50 dB(A)
Load (Spinning Disc)
51 dB(A)
54 dB(A)
The measurements were taken in my office with a noise floor of around 37 dB(A). At idle the new Xbox 360 slim is noticeably quieter, but still audible. The drop in idle noise is perfect for those of you who use the Xbox 360 as a HTPC of sorts. You can still get quieter out of a well designed HTPC however.
While spinning a disc the old Jasper was absurdly loud it is more bearable on the new 360. It’s still not silent (nor can it be while quickly spinning a disc) and you’ll still scratch discs if you move the Xbox 360 while a disc is spinning, but it’s an improvement.
The DVD drive lifts right out and you can disconnect the power and SATA cables from the unit easily just like on the older models.
This is a newer version of the Lite-On drive found in the newer Jasper Xbox 360s. They use the DG-16D2S while the Valhalla uses the new DG16-D4S.
Microsoft also outfitted the drive with a strip of rubber to help dampen vibration:
The piece of aluminum shielding in the lower left of the picture above lifts straight out, you can remove that if you want to pull out the motherboard.
The black piece of plastic in the upper right hand corner of the picture above is the HDD carrier. It’s actually mounted on a flexible mount to allow for some vibration dampening and shock resistance. There’s a single large T8 screw holding it in place, remove this screw.
The drive tray isn’t completely free yet, there’s one more T8 screw at the back of the Xbox 360 that has to be removed. It was hidden by the casing but with that off you can now access it. Remove that screw and the drive tray is free:
The Motherboard
Two phillips screws hold the fan in place. You don’t need to remove them to remove the heatsink but I did anyway:
The single large heatsink is a lot heftier than what we'd seen in previous 360s, it doesn't feel quite as cheap or as insufficient. This time around it has to do double duty cooling both the CPU and the GPU.
At this point I can easily remove the motherboard and flip it over, revealing our old friend: the x-clamp.
Place your flathead screwdriver tip here, pointing away from the xclamp, and pry the clamp off at this point. Repeat for 1 - 2 more and the whole thing should come off easily.
Unlike previous Xbox 360s, the Valhalla x-clamp isn’t a pain to remove. In fact all I had to do was slide a small flathead screwdriver in each of the four slots in the clamp and push down to make the clamp pop out. I’ve marked the area on the photo above.
With the x-clamp removed the heatsink pulls off revealing Microsoft’s Xbox 360 CGPU covered with a heat spreader. The heat spreader is great for making sure no one cracks a core while working on these things.
The chip to the left of the CGPU is the 360’s South Bridge, responsible for the SATA and USB ports in the system. The chip is marked as an A0 stepping which is usually the first stepping to come back from the fab. This is probably a pretty tried and true design by now with no bugs to worry about at this point.
Xbox 360 South Bridge (top), 16MB SLC NAND (bottom)
The Hynix NAND on the motherboard is still 16MB in size. It is SLC NAND so it should last the lifetime of the Xbox as long as you don’t somehow mod it into a database server.
The third major ASIC on the motherboard is the HANA scaler/video encoder chip we’ve seen before on Jasper.
The motherboard now has two SATA ports directly on the board itself to support the new HDD tray.
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Anand Lal Shimpi on 2010-06-21
