SLI/CrossfireX for World of Warcraft

SLI/CrossfireX is the term used for running multiple video cards in your computer and normally that would be 2 video cards. Not every video card supports running in SLI (Nvidia) or CrossfireX (ATI) and many motherboards out there do not support it either. Furthermore, most motherboards do not fully support or have the lanes/bandwidth to support to full PCI-e x16 lanes as many will support one x16 slot enabled but when adding a second card, the lanes revert to x8 lanes. The video cards must also match almost indentically when adding a second card; one can not add one Nvidia card and one ATI card and one can not add cards with different chipsets (if one has a GeForce 8800GT, one can not add a 7 series or 9 series card and most of the time, one could not even add an 8800GTX). The only way to really ensure SLI/CrossfireX will run is to get the exact same card from the same manufacturer of the original card! The picture to the left show 3 Nvidia GTX 280 cards in a tri SLI configuration. (Sidenote, there is something called Hybrid SLI that is for using completely different video cards but this is not a performance technology at the current time.)

Almost everyday I read a forum post about individuals thinking about running SLI/CrossfireX to get a performance increase in World of Warcraft. First off, World of Warcraft is a CPU intensive game as opposed to a GPU intensive game. (Many big games currently on the market are GPU intensive.) It used to be that one would have to edit a registry setting (cvar) to really get WoW to utilize more than 1 core (and in the last year, more than 2 cores). That is no longer the case as WoW can almost max out 2 cores and can run on 3 cores with no tweaks needed. WoW does support SLI/CrossfireX but for most it is not an upgrade path to better performance. At this point one may be recalling countless charts and tables of benchmarks showing the effectiveness of SLI/CrossfireX and that is true but with a caveat. Those benchmarks and tests also show results for GPU (video card) intensive games! Why would they use a game as a testing parameter that does not really tax the GPU? Warhead, Left 43 Dead 2, F.E.A.R. 2 and all the other games they use in their testing setups can really put a beating on the top end video cards and adding a second video card can help alliviate a system bottleneck between the CPU, the GPU and what you see on the screen (although one is still most likely bottlenecked by other factors and even more so when adding a second video card, but that is for a different blog post!) World of Warcraft does not push the video card as it primarily uses the CPU. That is not to say WoW does not look good because I love the visual styling and effects in the game. But it obviously does not have the same effects that are in first person shooters, racing games and the like that are full of explosions, detailed realism and environmental detail. Also, WoW is coded very well (not to say any of the other games are not) but good code can let the GPU relax a bit. The CPU is the true workhorse is WoW as the games uses a ton of preconfigured models, maps that are almost entirely static and, true to D&D form, thousands of 'dice rolls' and formulas being computed in every battle.

Lets look into this SLI/CrossfireX concept in WoW a little. If you have a video card that is on par with an Nvidia 8800 GT/GTS or an ATI HD 3870 or above, adding a second card will NOT increase performance (one may get a couple frames per second more, but nothing more than a trivial amount [frame rate increase under 5%]). If you have a decidedly slower/older video card, say an Nvidia 6800, you might get a decent performance improvement (% increase in frame rate) if one added a second 6800 card but part of that reason will be due to one's current frame rate being so low to begin with that even a 12-15 fps improvement could result in a frame rate improvement of 30%. However, I would not buy a 6800 card for ~$40 and take the hassle of finding the exact same card to run in SLI. I would just upgrade the card because adding a second 6800 would not increase one's DirectX or Pixel Shader version, does not improve one's memory interface, and would not allow one to fully saturate your PCI-E lane. It would be better to sell the 6800 card and buy an (for example) Nvidia 8800GTS for ~$75 (if the $40-50 price range is one's constraint) or an Nvidia GTS 250 for ~$110 (if one can get together another $40). Obviously one can buy an even better card if one's money constraint is at a higher price point. Either of those two cards would produce the same or more performance improvements versus using two 6800's in SLI.

Bottomline, going SLI or Crossfire solely to get an improvement in WoW is not the way to go. If one has a slower/older discrete video card such as the Nvidia GeForce 6 series or 7 series OR an ATI Radeon 9800, X700, X800, X1600, X1800, X1900, HD 2600, HD 3650, or HD 4650, then I would recommend just selling that card and buying a new card that is at minimum 2 generations newer (I would not go any lower than the Nvidia 8800GTS or the ATI HD 4770). The sweet spot for a discrete video card with Cataclysm in mind would be in the range of an Nvidia GTX 275 ($225) or GTX 280 ($325) or an ATI HD 5770 ($160) or HD 5850 ($310) -- any of those chipsets would give one very high performance even when Cataclysm comes out.

Using SLI/Crossfire as a method to achieving higher framerate for an Nvidia GeForce 9 series card or an ATI HD 3870/HD 4830 or better is pointless. That upgrade can cost one anywhere from $100-$400 and even at the $100 price point, the few frames one may get is just not worth it. That money could be much better spent upgrading the real bottleneck of your system and in turn, improving one's WoW performance.

A true Quad Core CPU would be a better upgrade if you are currently on a single, dual or 3 core CPU. Even a 3 core CPU is bottlenecking WoW to an extent that you would see more improvement going to a quad core as opposed to an SLI/CrossfireX setup. WoW can grab up to 3 cores for itself but it can not do that on anything less than a quad core or a Core i5/i7 CPU (I love AMD, although I am running an Intel Core i7 in my system, but this is just another reason why Intel CPUs are better than their AMD counterpart as an Intel CPU with hyperthreading can perform two different tasks on one core. Thus an Intel CPU that is dual core with hyperthreading can perform better in WoW than a 3 core AMD CPU with everything else about the CPU's being equal. [Note: I am not saying a dual core Intel with hyperthreading is better than a 3 core AMD, just that the Intel can handle 4 different tasks at one time versus 3 tasks on the AMD.]) Ok! Back to WoW and CPU core usage. The most WoW can utilize with a 3 core CPU is 2 cores as atleast 1 of the cores will be running background tasks; obviously WoW uses even less if one only has a dual or single core CPU (although in a dual core system, WoW can use both cores, but it can't max them as it could on a quad core as it is competing for the other core with everything else one is running, such as Windows, Anti virus, a web browser, etc.). Going from a single core CPU to a quad core CPU would be a massive increase in performance as World of Warcraft is always competing with everything else on one's computer for CPU cycles. Sidenote: This is a simplification of how the CPU works but there is not really that much more too it except a lot of complicated terminology

Upgrading to a better hard drive would also be a better upgrade than multiple video cards. If one's hard drive is in the 5000-6000 range for RPMs, an upgrade to a 7200RPM HD would be a huge improvement. There are also 10,000RPM HDs (which are coming down in price due to Solid State hard drives) that would give a decent improvement over a 7200RPM hard drive especially if one is using 4GB of RAM or less. Even if you are using 4GB of RAM, WoW is using your hard drive's page file regularly (this is different than the computer just accessing the HD to get WoW files, music, etc. -- the page file on a HD is a small portion of the HD that the computer uses like RAM). Even a page file on a 10,000RPM HD is significantly slower than your system's true RAM but nonetheless having a 10k RPM HD would increase the performance of WoW versus a 7200RPM HD. The true upgrade sweet spot here is if one does have a hard drive with an RPM of 5000-6000; upgrading to a 7200RPM or 10k RPM would be a massive improvement for WoW, let alone the system. Furthermore, if one's hard drive is a few years old, the buffer is most likely only 4MB or 8MB, the read/write access times are over 12ms, and the seek time is over 8ms. Any of the newer hard drives released within the last year will have a buffer of 16MB with a few featuring a 32mb buffer, the read/write access times are under 10ms and the seek time is under 6.5ms. That all adds up to more and more performance! But I can not just end this section without saying this -- if you are using a 7200RPM hard drive to play WoW or any other games and/or you use Photoshop, Dreamweaver, Audio/Video editing software, etc. and/or one compresses and decompresses a lot of files -- I just can not even explain how awesome a 10k RPM hard drive is. I have been using a 10k RPM hard drive since 2004 and before that I used an option called Raid 0 which used 2 7200RPM HDs to get a similar effect as a 10k RPM hard drive (a 10k RPM HD is much more simple than using a RAID 0 option too). A 10k RPM HD just makes the computer feel decidedly more snappy; everything justs seems to be faster and the lag time (ie. when the computer seems to be just sitting there for 1 second to many seconds thinking after one has clicked for it to do something) versus a 7200RPM drive is atleast cut in half. It is a quality of life upgrade, between upgrading to a 10k RPM hard drive and adding more RAM, there really isn't an upgrade that one can do on most decent computers that can give one an improvement in everything one does on the computer like those two upgrades!

Finally, another upgrade of sorts that would allow for more system resources to be available to World of Warcraft is to get rid of that free Anti Virus software everyone seems to be using. Most of the free scanners use too many CPU cycles and have a large memory (RAM) footprint. Some of the free options are coded to be inefficient so that a user would be more compelled to upgrade, which I think is a terrible strategy. All of the free anti virus scanners do not feature the most robust virus library and are weeks behind on current viruses versus their paid counterpart. Also, if you are using Norton or McAfee, while one would have a great scanner for keeping their system clean of viruses, malware and spyware, these two companies' scanners are unnecessarily bloated using more CPU clock cycles and more memory than even the free scanners! Solution: Try ESET NOD32 Anti Virus. This is the best anti virus software there is; one's system will be as safe or more safe than using Norton or McAfee and NOD32 has the smallest footprint of any anti virus program. It uses the least amount of CPU cycles and with all the bells and whistles turned on, NOD32 is using only 3.2MB of memory on my system right this second. Norton and McAfee can use 10 to 25 times this amount of memory easily. ESET NOD32 does cost money to use; they have no free version (~$40 a year) however they do have a free one month trial. I would definetly suggest trying it out for just the trial period and seeing how well it performs. $40 a year is also a small price to pay for complete piece of mind from viruses, malware and spyware. Check it out here.

In closing, simply, SLI or CrossfireX is not an effective way to get better performance from one's computer when playing World of Warcraft.