I agree with Justin, try the Omega drivers.
A few points to bear in mind:
1. I have them installed on my VGN-A115Z and it runs perfectly. You just need to be careful NEVER to use the overclocking facility (mobile chips just cannot take the associated increase in temperature for very long). On my machine DOOM3 runs in med-res (shadows off) at c. 35-40 fps (perfectly smooth and playable) and the Serenescreen Marine Aquarium went from c.60 fps to c.260 fps after I installed the omega drivers (remember this is without using overclocking!).
2. Omega Drive (the witer of these alternative drivers, OMEGA DRIVE! What kind of name is that !?!) writes some splendid drivers and has overcome many of the previous issues that his code had with laptops (i.e. DVD movies not runing properly).
3. Indeed, as I think someone else mentions, ATI (the company) complement him on his work!
4. Omega drivers are based on the ATI CATALYST (official desktop) drivers but are tweaked to work more efficiently and be more compatable with mobile chips (at least from the Radeon Mobility 9200 and higher).
There honestly isn't much alternative choice:
1. ATI do not support mobile chips - they say that drivers for mobile chips are the responsibilty of the vendor (in our case Sony)
2. Sony have never released any driver updates for 3D chips, only patches to solve issues with XP SP2 etc. They are unlikely to change their stance on this one. Addtionally, they won't release drivers that improve performance and/or prevent certain games (e.g. DOOM3) from freezing (which incidentaly is to do with the bad drivers that Sony supply / write, that come pre-installed)
3. There are no such things as upgradeable graphics chips on laptops, they are part of the mother board. Upgradable chips may occur in the future (see the news section of both the ATI and NVIDIA sites) but these will be part of as yet unreleased laptops (and Sony will, as usual, no doubt be very slow to adopt the technology)
4. The tool that allows CATALYST drivers (the official ATI ones) to be installed on laptops should be used with caution! They are simply NOT WRITTEN FOR MOBILE chips. The Omega drivers are adapted to do this (i know, i've looked at the code).
Hope this helps
CW
PS I cannot guareentee how well the Omega drivers work with older chipsets (i.e. pre Radeon Mobility 9000 etc)
PPS I am not Omega Drive!
PPPS I am not affiliated in any way with Omega Drive!
PPPPS I am not a Sony hater....
.... I love my Vaio and my many other Sony products. I think they have a real talent for design and technological acheivments. However, they seem either to know very little, or simply don't care, about the OS and software in general installed on their machines. This is a shame as Vaio's in general are very good (aside overheating, HDD's not being optimised, memory being mis-configured etc.) it just that they are let down by sometimes dubious installations and chronic lack of support!
Sony need to improve. I am quite determined that Sony LISTEN to me and more importantly TAKE ACTION.:smileylaugh: So I sound convincing? LOL Will you back the Sony Revolution?:smileylaugh: 
