In our mini-review of the Xbox One I speculated that the shipping version of Microsoft's console featured 14 AMD GCN CUs (Graphics Core Next Compute Units), with two disabled to improve yields. Microsoft publicly stated that Xbox One development kits featured 14 CUs and Sony similarly had 20 CUs with only 18 enabled with the PS4. With Xbox One hardware in the wild, Chipworks went to task delayering the SoC/APU and confirmed the speculation - the Xbox One does indeed feature 14 CUs (pictured above).

Microsoft claims it weighed the benefits of running 12 CUs (768 cores) at 853MHz vs. 14 CUs (896 cores) at 800MHz and decided on the former. Given that the Xbox One APU only features 16 ROPs and ROP performance scales with clock speed, Microsoft likely made the right decision. Thermal and yield limits likely kept Microsoft from doing both - enabling all CUs and running them at a higher frequency. Chances are that over time Microsoft will phase out the extra CUs, although it may take a while to get there. I'm not sure if we'll see either company move to 20nm, they may wait until 14/16nm in order to realize real area/cost savings which would mean at least another year of shipping 14/20 CU parts at 28nm.

Compared to the PS4's APU, we see a very similar layout. The on-die SRAM sits next to the GPU array, and far away from the CPU, which makes sense given that the latter isn't allowed direct access to the eSRAM. You can very clearly see the tradeoff Microsoft had to make in order to accommodate its eSRAM. The GPU area shrinks considerably.

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  • andrewaggb - Wednesday, November 27, 2013 - link

    I bought an XB1. I knew it was slower than the PS4, but quite frankly both are much slower than my PC so that wasn't really a factor.
    If I can get it on PC I always pick PC. I got XB1 for the things I can't get on PC, which is essentially Kinect, some exclusives (Halo), some console only titles (like skylanders), stuff like that.

    So far I find my power brick too loud, so I put my system in low power mode, (longer startup time, no updating when off), which is a downer.
    I also found the TV integration was kinda lame because unless I missed something, it doesn't seem to have Canadian channels listed, so I ended up not bothering with the TV integration after trying it out for a couple days.
    Live TV also froze a couple times and wouldn't work again until I unplugged the HDMI and plugged it back in. This may have been a cable issue as it felt like it only went in 95%, but I didn't bother diagnosing it further.
    Kinect voice controls work fairly well for me, but my kids are hit or miss. Image recognition is great for me, so so for my younger kids.

    Skype was ok, but kinect's camera really washes out with lights in the background, I've moved which TV it's on now and might try skype again.

    So... I'm a bit disappointed. Killer instinct is fun, the new controller is substantially lighter than the previous one, kinect does seem to be quite a bit better, but it's not awesome by any stretch.

    I played a blu ray movie, it worked ok, though I think there was the occasional hiccup (like a dropped frame or something).

    I've contemplating trying to send my power brick back, I called in on day 2 of having it and it sounded like I had to return the entire console.

    Anyways, in my opinion, it's ok... but not awesome.
    Reply
  • andrewaggb - Wednesday, November 27, 2013 - link

    And to be clear about my power brick issue, there is a fan in the power brick, that if you have your console in quick start mode/instant on, whatever the fan seems to stay on 24/7 or something. In a quiet room I could hear it very clearly and found it completely unacceptable. Some other people report the same issue, but other's don't, so I could just have a loud fan/bad power brick.

    Something to be aware of anyways.
    Reply
  • Andromeduck - Wednesday, November 27, 2013 - link

    what really? there's a fan in the power brick?! Reply
  • bill5 - Wednesday, November 27, 2013 - link

    I would like to comment on one of Anand's comments, that MS likely couldn't both enable 2 CU's AND hit 853 mhz.

    I guess this could well be true, but I also think it's a very strong possibility MS just blanched at the yield expense of enabling the 2 redundant CU's (whereas presumably a 53 mhz upclock might have cost them next to nothing). Which imo, was a very shortsighted move if they did so.

    I really really wish MS had enabled those 2 CU's. At that point you'd have a 1.5 teraflop system, with more CPU speed (due to higher clock) and more peak bandwidth than PS4. In other words you'd probably have essentially a hardware "tie" with PS4 at worst.

    I'd also of course preferred a larger GPU upclock, considering AMD GPU's around 10-14 CU's easily are sold stock at 1 GHZ and up.

    I have a hunch MS prioritized a quiet, living room friendly machine over any noise increase at all with more performance, and I would disagree with that priority.

    I also heard a possibly technically knowledgeable source tell me he thinks MS may not have clocked the GPU higher because it would have "destroyed the timing windows" on the ~doubling of ESRAM bandwidth that was "discovered" by MS a few months ago. I have no idea if that idea has any technical validity whatsoever. But if that's the case, then I can understand why MS wasn't more aggressive on the GPU clock, as increasing the GPU clock slightly in exchange for halving the ESRAM BW likely would have been a major net negative on performance, obviously.

    Anyways, I have a feeling MS's minor, late, CPU and GPU clock increases probably were just enough to really put a fly IN PS4's ointment to where PS4 wont show major graphical superiority over Xbox One in the future. Typical devious, smarter than Sony, Microsoft...

    I would also say there was a lot of generic FUD on Neogaf about how PS4 was just going to obliterate XB1 by even more than the gap suggests such as:

    -XB1 has effectively only 68 GB/s bandwidth (these people willfully ignored/poo poo'd ESRAM) and thus will be destroyed/crippled.

    -XB1 wont allow "coding to the metal", therefore will be brutally crippled as opposed to PS4

    -PS4 would have 7+GB of RAM available for games vs 5GB for XB1, would have 1/0 CPU cores reserved for OS vs 2, the list really went on and on.

    It appears none of that FUD materialized at all, and in real terms XB1 is "keeping up" just fine.
    Reply
  • Andromeduck - Wednesday, November 27, 2013 - link

    1M sales in NA vs 1M world wide

    you decide
    Reply
  • r47 - Wednesday, November 27, 2013 - link

    realy? do you know the price difference between US and the rest of the world?
    as an example... the ps4:

    ps4 US -> 399$ (=245$)
    ps4 UK -> 349£ (=567$)

    and same goes for Xbox...Im not saying that ps4 is going to sell more or less than xbox.. but you should take many things in consideration...
    oh, and by the way.. world wide is not only 13 countries.
    Reply
  • Zingam - Friday, November 29, 2013 - link

    You Brits shouldn't complain about prices! You are rich and if you need money you can always extort the colonies!

    There are more than 13 countries? Send the marines to destroy them!
    Reply
  • darkfalz - Saturday, November 30, 2013 - link

    I've got a Sony TV and BluRay home threatre system, but the thing is I hate the Playstation controllers, always have... but I'll sit this round out as the only reason I really bought an Xbox 360 was to play some SEGA Dreamcast sequels released only for XB/360 and SEGA are porting most of their stuff (albeit badly in most instances) to PC. PC is just much cheaper too in terms of games cost and I don't need to stick a new disk in every time. Reply
  • tipoo - Thursday, November 28, 2013 - link

    I still dont' think it would be a tie, so long as the PS4 still had double the ROPs and TMUs. The ONe could have 40 compute units for all the help it would do to being output limited to 16 ROPs. Reply
  • TheinsanegamerN - Monday, December 2, 2013 - link

    if the one had 40 compute units it would haveroughly 30 ROPs. ROP count scales with CU count. Reply

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