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DirectX 9 Versus DirectX 11

World Of Warcraft: Cataclysm--Tom's Performance Guide
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Blizzard's World of Warcraft 3D engine is said to center on a modified Warcraft III engine, which required DirectX 8.1. With that said, World of Warcraft now employs a DirectX 9 code path, extending compatibility to a broad range of modern graphics cards dating back to 2003.

Of course, gamers get excited about subsequent versions of DirectX (or OpenGL, for that matter) because they often herald a new generation of effects and technologies developers can use to augment realism. But a new API doesn't necessarily have to center on beautiful new features; it can also introduce more efficient ways of doing things already seen today. We saw that recently with Firaxis' Civilization V, which uses DirectX 11 to help improve performance (rather than introduce new eye candy).

As it turns out, Cataclysm incorporates experimental support for DirectX 11, and rather than adding anything visually, it's designed to help speed up performance, too.

Of course, if you want to take advantage of DirectX 11, you'll need a DX11-capable card from AMD's Radeon HD 5000/6000 lineup or Nvidia's GeForce GTx 400 series. You can't enable DX11 through a graphical option. Rather, you'll need to add '-d3d11' to your World of Warcraft shortcut. Or, open your config.wtf file (located in ...\World of Warcraft\WTF\) and add the line SET gxApi "d3d11".

What sort of gains can you expect to see? Much to our surprise, they're significant.

Using a GeForce GTX 580, frame rates jump more than 30% at 1680x1050 and 1920x1080--two resolutions that are processor-bound for this fast card, not graphics-bound. Moving up to 2560x1600 cuts the gain to 22%. Though still not bad, this shows that DirectX 11's mechanisms for improving threading and memory handling can greatly speed up rendering, so long as there is not some other bottleneck limiting performance.

AMD's Radeon HD 5870 sees similar benefits as the GeForce card at 1680x1050. Because it's not as powerful, those gains erode a bit at 1920x1080 and evaporate almost entirely at 2560x1600 once the card can no longer outpace our powerful processor.

In what almost seems like a stroke of irony, it looks like the folks most likely to see big speed boosts at the hands of Blizzard's DX11 code path are the ones with fast processors and near-overkill GPUs. If you built your PC with balance in mind, there shouldn't be as much room for API optimizations to augment performance beyond what you're already seeing. With that said, I've been passing this DirectX 11 flag around to a number of friends with lower-end Core i5 and Core 2 Quad configurations, and they're all seeing roughly 20 frame per second performance boosts. So long as your GPU is DirectX 11-capable, there's a fair chance that enabling Blizzard's code path will at least do something for your gaming experience.

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  • 25 Hide
    SpadeM , December 6, 2010 5:50 AM
    I'm impressed, if Chris went to all that trouble to benchmark the new expansion for a mmorpg in such great detail it can me only 2 things:
    1. Chris is a closet WoW-player
    2. Really bored
    With that said, i really do hope to see more of these articles, albeit with a more demanding title on the bench, even if it's from a "lesser" developer/publisher combo.

    PS: I do hope ppl appreciate my sense of humor :p 
Other Comments
  • 9 Hide
    Odem , December 6, 2010 4:51 AM
    Kind of unfortunate to see if I had gone with an i5 750 instead of a 955 I'd be seeing more fps. Although the money I saved for the same frames in most other games leaves me happy.
  • 5 Hide
    Anonymous , December 6, 2010 4:58 AM
    WOW only uses 2 cores by default. However youc an configure it to "quasi" use more cores. you have to manually edit your config.wtf and change the variable: SET processAffinityMask "3" (3 is the default meaning 2 cores) to the following values for respective processors:

    i7 Qudcore with Ht- 85
    Any Quadcore chips with no HT - 15
    i5 Quadcore which does not have HT as far as I know - 15
    i5 Dualcore with HT- 5
    Dualcore with HT- 5
    Dualcore without HT - 5
    AMD tricore - 7

    There used to be a blue post explaining the settings and how to calculate it for different cores. But the old forums got wiped.
  • 5 Hide
    sudeshc , December 6, 2010 5:12 AM
    not a that big fan of wow, but still happy to see that they do keep in mind that people also have low end hardware too.
  • 25 Hide
    SpadeM , December 6, 2010 5:50 AM
    I'm impressed, if Chris went to all that trouble to benchmark the new expansion for a mmorpg in such great detail it can me only 2 things:
    1. Chris is a closet WoW-player
    2. Really bored
    With that said, i really do hope to see more of these articles, albeit with a more demanding title on the bench, even if it's from a "lesser" developer/publisher combo.

    PS: I do hope ppl appreciate my sense of humor :p 
  • 2 Hide
    dirtmountain , December 6, 2010 5:51 AM
    Damn fine job Mr. Angelini, the most comprehensive hardware guide i've ever seen for WoW. This will save me hours, if not days of time when talking to players about their systems. Much appreciated.
  • 8 Hide
    Bluescreendeath , December 6, 2010 5:51 AM
    The Intel CPU scaling part was lacking...i7 980X at 3.7GHz? For WoW? Really?

    And why only Corei CPUs? Where are all the Core2s? 75% of Intel users still use Core2s and 775s!
  • -2 Hide
    voicu83 , December 6, 2010 5:56 AM
    i hate you so much tom's hardware ... now i have to go buy an intel proc instead of my phenom ii x4 :D  ... and add a dx11 board on top of it ... oh well, there goes my santa's gift :p 
  • 0 Hide
    Moneyloo , December 6, 2010 5:57 AM
    Simply astounded by the time and effort that must have went into this piece. It also makes me greatly look forward to my new Maingear desktop arriving on the 23rd just in time for Christmas. Dual OC gtx580s in sli with a corei7 FTW. Ultra everything here I come!
  • 5 Hide
    cangelini , December 6, 2010 5:59 AM
    SpadeMI'm impressed, if Chris went to all that trouble to benchmark the new expansion for a mmorpg in such great detail it can me only 2 things:1. Chris is a closet WoW-player2. Really boredWith that said, i really do hope to see more of these articles, albeit with a more demanding title on the bench, even if it's from a "lesser" developer/publisher combo. PS: I do hope ppl appreciate my sense of humor


    It's a little easier to talk about WoW since I've been playing it for way too long, but I definitely want to see us doing more comprehensive coverage of demanding titles on launch day. It's all a matter of trying to convince the software guys to give a hardware site early access to the game. That's the hard part :) 
  • 0 Hide
    mitch074 , December 6, 2010 6:38 AM
    With hardware-accelerated cursor now enabled, OpenGL has finally become usable in WoW; was there any testing done on that? Not only does it sometimes give a boost to Nvidia cards, it's also the 'default' setting for Linux players - incidentally, the ones who were asking for the feature for a while.
  • 2 Hide
    cangelini , December 6, 2010 6:44 AM
    Mitch, the hardware cursor was enabled for all testing. That's one of the features I wouldn't turn off unless I was having problems--none of these configs encountered any errors with it enabled.

    It's worth noting, however, that Nvidia told me SLI support required hardware cursor to be enabled. It didn't seem to make a difference in getting SLI working, though. According to the company, it filed a bug report after I submitted my initial testing results a couple of weeks back and they confirmed SLI wasn't scaling.
  • 1 Hide
    Twoboxer , December 6, 2010 6:58 AM
    Thanks very much for finally giving us some data to hang our hats on answering questions about WoW hardware and performance. I've long known that SLI hurt, not helped, FPS in EQ and EQ2, but got laughed at when suggesting WoW players not depend on SLI/xfire. I couldn't prove it because I had abandoned SLI by then. Vindication feels good.

    I wonder if you have any info on another general statement that may not apply to WoW . . . that more than 4GB of memory doesn't help games. The three WoW PCs that I run have too many differences to prove the point, but I get inexplicable relative frame rates on an 8GB 64-bit Windows 7 machine with a 5750 compared to a 4GB 32-bit WinXP machine with a 5870. While this could be due to different Intel cpus, mobos, chipsets, etc, I keep thinking getting the OS, Ventrilo, various Logitech and Zboard drivers, Norton, etc out of WoW's address space allows WoW to run as freely as possible. Any thoughts?
  • 0 Hide
    Twoboxer , December 6, 2010 7:08 AM
    Quote:
    WOW only uses 2 cores by default. However youc an configure it to "quasi" use more cores. you have to manually edit your config.wtf and change the variable: SET processAffinityMask "3" (3 is the default meaning 2 cores) to the following values for respective processors:
    That parameter doesn't exist in the two config.wtf files I have access to.
  • 0 Hide
    elcentral , December 6, 2010 7:11 AM
    lol my poor 295 only working one of the 260 cards in it well wow newer had a to good engine and they sure hawent made the 295 sli work yet.
  • -6 Hide
    FunSurfer , December 6, 2010 7:43 AM
    cpu with 6 cores and gtx580 for a game that don't look much more better than Unreal! beh! save the planet! conserve power!
  • 5 Hide
    Fokissed , December 6, 2010 9:16 AM
    TroyrobertsWOW only uses 2 cores by default. However youc an configure it to "quasi" use more cores. you have to manually edit your config.wtf and change the variable: SET processAffinityMask "3" (3 is the default meaning 2 cores) to the following values for respective processors:i7 Qudcore with Ht- 85Any Quadcore chips with no HT - 15i5 Quadcore which does not have HT as far as I know - 15i5 Dualcore with HT- 5Dualcore with HT- 5Dualcore without HT - 5AMD tricore - 7There used to be a blue post explaining the settings and how to calculate it for different cores. But the old forums got wiped.

    The number is calculated with binary addition, you can specify which cores you want WoW to use by setting the affinity mask to the binary number that represents the cores used:
    core0 - 1 (2^0)
    core1 - 2 (2^1)
    core2 - 4 (2^2)
    core3 - 8 (2^3)
    core4 - 16 (2^4)
    core5 - 32 (2^5)
    Add these numbers up to get the affinity mask that suits the processor:
    Dual core - 3 (11)
    Tri core - 7 (111)
    Quad core - 15 (1111)
    Hexa core - 63 (111111)
    Using binary numbers as boolean values for each core (right to left) will convert into the affinity mask needed to use those cores.
  • 3 Hide
    Fokissed , December 6, 2010 9:18 AM
    Quote:
    That parameter doesn't exist in the two config.wtf files I have access to.

    Add it.
  • 2 Hide
    BWMerlin , December 6, 2010 10:16 AM
    I am really glad that Tom's has finally got around to giving a detailed review of WOW performance on different hardware (would of like to seen some older and lower hardware as I an many other started playing WOW on far older hardware then what was reviewed).

    This game is massive and has been for years and yet every new CPU, RAM, HDD and GFX review completely ignores it (I do understand that it's hard to benchmark WOW but still something could of been worked out) it's about time Tom's works out some way to do benchmarks with it and include it.
  • 0 Hide
    dallaswits , December 6, 2010 10:21 AM
    My Phenom 945 and my ATI 5850 seem to rock along pretty well in WOW.
  • -1 Hide
    karma831 , December 6, 2010 10:57 AM
    Was pretty sad to see the i3 beating all the AMD cpus and the GTX 460 beating all the AMD/ATI gpus =(
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