CPU and GPU Scalability
What do we mean when we talk about scalability, be it on the CPU and GPU? Well, simply put, scalability is the rate at which performance scales with clock increases. For example, Core 2 Duo scales well with clock increases.However, when we talk about CPU and GPU scalability, we're not talking about increasing their clocks - we're talking about will the graphics card be able to keep up - offer a performance increase - if we were to use a higher clocked processor. The overclocking potential of Core 2 Duo platforms allows us to test GPU scalability. If a card performs better - offer higher frame rates - with a higher clocked processor, it means the benchmark is still system limited. Another, more interesting way of looking at this is that we have not hit the graphical limits of that particular graphics card.Why is that important? Well, that's related to the next question - why do we care about scalability at all. Well, the answer is again very simple. Having a graphics card that scales nicely means we will still be able to enjoy higher frame rates should we opt for a processor upgrade down the road. So, there's still a valid reason to hang on to that graphics card. With multirendering solutions like Crossfire and SLI, we can opt to get a second card similar to what we have rather than buying a new, faster card.
Generally, articles about scalability only uses average fps to measure performance and increase in performance. We don't think this approach offer a complete picture of scalability. Games and benchmarks vary in loads, sometimes we are more system bound, other times we are more graphics bound. There will be cases where the average frame rate will fail to indicate any increase from the use of a higher clocked processor. However, when we also look at the minimum and maximum fps, chances are we can see a difference. If minimum fps increase with the use of a higher clocked processor, then that benchmark still scales well - assuming the point where we experience minimum fps are the same. After all, having higher minimum fps usually means higher low frame rates, which should help the gaming experience considerably.
Performance
We ran tests with three different configurations - at Core 2 Duo E6300's default clock (1.86 GHz), then overclocking it to 2.4 GHz (6 x 400 MHz) and 2.8 GHz (7 x 400 MHz). Memory clocks were set to DDR2-800 and timings used were SPD timings. To keep relevance to actual gaming settings, we benchmark the games using our usual graphical test settings, not lowered settings to 'induce' system limited situations. Older games like Call of Duty, Homeworld 2 and Richard Burns Rally are very system limited with fast graphics cards, even with cards such as NVIDIA GeForce 7900GS and ATI / AMD Radeon X1950 Pro. This represent the 'optimal' scaling test. Newer games such as F.E.A.R, Quake 4, Serious Sam II may behave differently as we will see later on. We also included two new games in addition to The Elder Scrolls IV: Oblivion - the arcade favorite Need for Speed: Carbon and the heavily simulation oriented GTR 2.Graphical settings for these games are set to their highest possible values. Notable differences are F.E.A.R where we disable "Soft Shadows", Quake 4 where we use High Quality - not Ultra Quality - but anisotropic filtering was set to "1" for default tests and "16" for AA / AF tests. We used Serious Sam II built in "Maximum" quality preset then change resolution and AA / AF settings accordingly. All of these settings can be seen here. Our TES IV: Oblivion settings are as close as we can get to Ultra High Quality - you can see our test settings here. For Need for Speed: Carbon, we used the game's "Maximum" video quality preset, but change the filtering to "Trilinear" for default tests - AA AF tests are run with "4x" and "Anistropic" (talk about your typos, come on EA!!). NFS: Carbon test were done with the Sprint Race on Lincoln Boulevard. Below are the settings we used for GTR 2 Clear weather was used for our run of Monza GP tests.
Image quality settings in the Forceware driver for the NVIDIA GeForce 7900GS was set to "High Quality". We did leave the "Threaded Optimization" on, but all other optimizations are turned off (trilinear, anisotropic sample and mip filter optimizations). Based on past experience, at these settings image quality is comparable to ATI's default image quality settings. V-sync was turned off on both cards via the driver control panel and also through in game settings whenever possible. For some games (Call of Duty, Homeworld 2, Richard Burns Rally,GTR2), we force AA and AF through the driver's control panel.
Our test setup
Intel Core 2 Duo E6300 socket LGA-775
4 x 512 MB A-DATA Vitesta 5-5-5-18 PC6400 DDR2-SDRAM
Gigabyte Radeon X1950 Pro 256 MB graphics card
Leadtek PX7900GS GeForce 7900GS 256 MB graphics card.
Gigabyte P965-DS3P Intel P965 motherboard
Maxtor DiamondMaxPlus9 80 GBs Serial ATA 8 MB buffer
LiteOn 1673S DVD-RW
Tagan TG530-U15 530 watts ATX/BTX power supply
Windows XP Professional with Service Pack 2 installed
ATI Catalyst 7.1 reference driver
NVIDIA Forceware 93.71 reference driver
Intel Chipset Software Installation Utility 8.1.0.1006
DirectX 9.0c
all respected games used for benchmarks have been updated to their latest, final builds.
We'd like to thank Gigabyte for providing the Gigabyte P965-DS3P motherboard and the Gigabyte Radeon X1950 Pro graphics card for this test. We'd also like to thank Leadtek for providing the PX7900GS TDH and Tagan for the Tagan TG530-U15 power supply.
[Previous Page]
[Go to top]
[Next Page]