I’ve been happily pottering on with a 512MB Sapphire Radeon HD 4850 for some time now, but the recent release of an official high-res texture pack for Skyrim was the final motivation to make a change.

I was lucky enough to come by a free(!) NVIDIA Fermi-era MSI N470GTX board, with 1280MB memory. What’s interesting is what’s changed and what hasn’t…

The N470GTX is a double-slot card which largely mimics the 470GTX reference design. Despite warnings that this makes is a relatively loud and hot-running card, it is significantly quieter both idle and under load than the older ATI card. It does, however, require two 6-pin PCI-E additional power cables compared to the one which the older card required. This might go to explain why the NVIDIA board consumes in the region of 100W more power than the ATI.

I’d always found booting Ubuntu Linux on my system a somewhat hit-and-miss affair: Under Ubuntu 11.04, it worked about five attempts in six with the other attempt locking-up during early boot. After upgrading to 11.10, Ubuntu simply would not boot at all – it always hung immediately after enabling all processors. I could still boot from physical disk under VirtualBox running on Windows.

I must admit that I’d always assumed that this was a AMD Phenom II X4/AMD 790FXT compatibility issue… until I accidentally booted Linux with the NVIDIA card installed! I’ve tested this since on cold boots, warm boots, booting after having used Windows – and in every case, everything worked perfectly. This is interesting – an AMD card in an AMD-based system seems to be less compatible than third-party hardware. The AMD card was always fine under Windows, however.

On Windows, however, the NVIDIA card is somewhat less successful: the first attempt at running Skyrim resulted in frequent on-screen corruption with a single pixel-high line of green static being rendered from various different points on screen to the right-hand edge. Interestingly, this is exactly the form of corruption I remember seeing on friend’s machines years ago which led me to tending towards ATI over NVIDIA. Several driver re-installs and a Safe-mode use of Driver Sweeper*, and this problem disappeared.

What was still an issue, though, was that after a variable amount of time – sometimes only ten minutes or so but sometimes almost an hour – the game would freeze momentarily, then freeze and blank to black, then show texture artefacts and corruption before dropping back to Windows with a “Display driver stopped responding and has recovered” message. This happened on every attempt to play Skyrim. Luckily MSI do provide a reasonable set of tools for their graphics cards, and I found that dropping Core, Shader, and Memory clocks by around 1% fixed this also.

So the NVIDIA option is quieter, faster, and more compatible for non-Windows usage than the older ATI card – but at the same time it is much more power-hungry and does not run correctly without reducing the card’s performance.

It should be noted that the ATI card is now three generations out of date, whilst the NVIDIA card is last-generation and second-hand. Results with brand-new hardware may well be different – but the AMD Linux observation is still relevant, and I can’t help remaining a little concerned that NVIDIA vendors especially are pushing higher and higher clocks at the expense of stability.

* Note that I’m recommending this software necessarily – I’ve read reports that it can prevent your system from booting if not used carefully. YMMV