I can't find any reviews of the PCI version of the Radeon HD 5450 (at least I think your card is a 5450). The specs of the 5450 show that although it has a higher fill rate than a GeForce3 it actually has less memory bandwidth. Then there's obviously the PCI bus holding it back. Granted I am surprised it's that slow at RTCW which I think is only Quake III based and as you noted should be playable on a GeForce 2 MX. Your observation that 640x480 isn't any faster than 1204x768 suggests the problem isn't the raw capabilities of the video card - there's probably a driver issue or a CPU/platform issue. It wouldn't surprise me if AMD didn't properly optimize their driver for the PCI cards, as by ~2009 nobody in their right mind would be seriously gaming using a PCI graphics card.

You might have more luck with an older PCI graphics card, like a GeForce FX or GeForce 6 series. Does the motherboard have integrated graphics? What kind of performance do you get out of that?

Good suggestion, thanks! I found some time yesterday to experiment a little bit.

First, I've pulled out the radeon and installed drivers for the Intel GMA865 integrated graphics:

UT99 (CTF-Face), lowest FPS when looking over map, 1024x768 all high
D3D - 34FPS
OpenGL - 38FPS

RTCW, all settings maximum
640x480 - 32FPS outdoor, 60FPS indoor
1024x768 - 30FPS outdoor, 40FPS indoor

Next, uninstalled the GMA drivers and put in a Quadro NVS280 I had lying around. I didn't use this at first since it's only 64Mb, compared to the 512Mb of the Radeon. It should be roughly equivalent to a FX5500. The card has a tiny passive heatsink that is wholly inadequate, especially in a tightly packed system like this. After a first run the heatsink got so hot you couldn't touch it. I added a little fan for now.

UT99 (CTF-Face), lowest FPS when looking over map, 1024x768 all high
D3D - 60FPS (with some jerking when turning)
OpenGL - 60FPS, smooth

RTCW, all settings maximum
640x480 - 48FPS outdoor, 90FPS indoor
1024x768 - 35FPS outdoor, 60FPS indoor

These results at least make a lot more sense. Even the integrated graphics performed better than the radeon, so there is definitely something iffy going on with that. The performance with the NVS280 is definitely going in the right direction, but seems limited by its 64Mb at 1024x768. Ideally I'd like to have a card with 128 or 256Mb in the FX or GF6 series, but for now this is passable (I can always play in 640 of course).

What a bit of luck, I came across the website of a local computer recycler that had a PNY GeForce 6200 PCI - 256Mb, for 30 euro's.

This card should be in the sweet spot of power vs compatibility. With a newer driver, I tried the same benchmarks again:
UT99:,CFT-Face, 1024x786 all high
OpenGL: 60fps
D3D: 60fps

RTCW, all settings max
640x480: 60fps outdoors, 91 indoors
1024x768: 47fps outdoors, 70 indoors

With the 47-70fps I now get in RTCW, it is definitely playable. So, mission accomplished!
It was fun pushing this PCI-only machine to do some early 2000's gaming, but I'm not sure I would recommend it. Trawling my local craigslist yielded only three actual PCI cards, with hundreds being wrongly labelled PCI-e cards. Early PCI-e cards are really in the 'junk' phase of the price curve, starting at only a few euro's. AGP cards were also still around, but getting thin. Good thing with AGP is of course that you can work with the top-end cards, rather than the bottom of the rung stuff they used for PCI.

Nice find. I'm glad you're getting the results you wanted!

I agree, a PCI-only machine is generally a constraint that is tolerated due to form factor (eg your case matches your monitor and keyboard and it would be a shame to break that apart). There were very few PCI graphics cards with good 3D performance, and it's not like you're going to buy a Voodoo 5 5500 PCI these days...

I don't think it has anything to do with the card's performance.

Try renaming the game's exe to quake3.exe. That sped it up tremendously on a HD 5770 I played it on years ago. It was getting ~20 fps too. Basically ATI used app profiles that activate based on executable to configure compatibility aspects and RTCW was not something they tested anymore.

With PCI and a card with 512MB VRAM I think the bottleneck that is a concern is geometry saturating the bus. So the more advanced the game the worse that will get. 512MB VRAM is certainly enough texture storage for anything you would run on a HD 5450.

You might want to keep an eye on temps. Those passive coolers are often barely adequate and it might thermal throttle. I don't like em.