DX9 and DX10 performances

DX9 and DX10 performances

The first thing we can conclude from this graph is that performances in Windows XP remain slightly superior in mono-GPU mode and are sometimes clearly higher in multi-GPU mode as we can see in Bioshock and Rainbow Six Vegas which both use the Unreal Engine 3.0. F.E.A.R., however, displays the opposite behavior as results in SLI noticeably increase in the transition from XP to Vista.

The evolution of performances in Vista, however, is weak or at least far from what we could have expected base on Nvidia’s enthusiasm of its newest drivers. They do add a gain in Bioshock and Rainbow Six Vegas, but this is nowhere near to the result in XP.

Note that the 163.67 driver causes several bugs in Oblivion and F.E.A.R. menus once SLI is activated. These problems disappear with the 163.69 and 163.71.

DirectX 10 performances

While performances are more or less stable in Lost Planet which received direct advanced support as Nvidia obviously wanted to have good results in the first DirectX 10 benchmarks, this isn’t the case for Bioshock. In DirectX 10 mode, results are sometime inconsistent. With a single GPU, there are improvements in going from the 162.xx to the 163.xx, however, with multi-GPUs they go down! Nvidia evidently has some work to do in this area.

Note that the 163.67 driver causes cuts in fluidity in Lost Planet although performances are only slightly affected.

DX9 and DX10 gains

DX9 and DX10 gains

These numbers show the progress of Vista’s new drivers as much as they show how far behind they are compared to those of Windows XP.

DirectX 10 gains

We noticed a problem with Bioshock in its DirectX 10 version. While SLI shows a slight gain with the 162.22 driver, more recent ones cause a reduction of performances.

Conclusion

Conclusion

In this quick test, we were able to actually see some progress for SLI support in Windows Vista. Performances do indeed increase with the latest drivers and bugs are reduced. Having said this and although Nvidia has decided to strongly insist on SLI at this moment, nothing however has been radically improved. It’s more of a continuous evolution, and there is still some work to do as we see in Bioshock's performances in DirectX 10 mode.

If Nvidia is now highlighting SLI, it’s to prepare for the release of its new chipsets by taking advantage of the arrival of a certain number of new games that don’t have a dedicated profile in older drivers. If we tested only these new games, we could have seen a big evolution mostly due to SLI not yet being activated (or correctly so) in the absence of adapted profiles in older drivers. This wouldn’t be because drivers increased performances.

A propos, this system of profiles remains one of the large weaknesses of multi-GPU technology. It requires that drivers be updated with the arrival of new games and this should be done well before their release. Producing a new driver is not as easy as we might think due to the whole validation process and for this reason, maybe it’s time to think of a better adapted system. Perhaps by separating the core of the drive from the profile part so that it could more easily and quickly be updated?

As for the interest of SLI, whether it’s with Windows XP or Vista, we think it fits into the high end and allows the construction of systems that are not yet feasible with a single graphic card. Using 2, 3 or 4 cards has an interest even if it is a rather small niche.


Finally, the idea of buying a mid-level graphic card and then later buying a second one to update a configuration doesn’t seem that enticing given the rapid evolution of GPUs. This opinion doesn’t sit well with Nvidia who is partly counting on users that will opt for one of its chipsets allowing this possibility. However, experience has shown that this is rarely the case and a model is often replaced by a single more recent one. This is confirmed by Steam user statistics which indicates that in over a million gamers, only 1% use more than one graphic card in their PC.