I suspect that the USB ones won't be any good, as they're most likely too slow.

The cad packages (particularly one PCB package I use all the time) redraw the screen constantly. I have found to my disgust that the new cards are MUCH slower than the 4.5 year old cards they were meant to replace, to the point that as I pan around in the package it takes (depending on amount of detail on the screen) up to about 2 seconds each time the screen redraws. This is unusable. I can't imagine that doing this over a USB link would be any faster.

The HD3850 cards do the same thing sufficiently fast that there is no perceptible lag. It's really massively annoying. Aside from anything else it means I've wasted £120 on a pair of cards that make the machine slightly quieter at the expense of making it so slow as to be useless. I've temporarily worked around it by making sure that the two monitors I do most of the CAD work on are connected to the 3850 card, but even so it's a real pain.

I can't believe how slow the things are. A memory bandwidth test program I found claims that the 6570 has a fill rate of around 30GB/s as against the the 3850's 45GB/s, but the visible speed difference is much much bigger than those figures would suggest. You'd think that in nearly five years of development ATI would have managed to improve the performance, not kill it so comprehensively.

I'm going to see if I can return them on the basis that they are only two port cards even though they were sold as three port ones, but I suspect I've basically thrown my money away.

The other annoyance is that the latest video drivers are too smart for their own damn good. In the old days, if I unplugged a monitor in a multi-monitor setup, that particular monitor would, unsurprising, go black. But that would be the only real result. So I could swap the physical connections around at will to test different monitors on different ports.

The new drivers are MUCH more clever than that, and know what I wanted better than I do So when I unplug a monitor, the computer detects this, and decides that I really wanted to shuffle the order of the remaining ones around instead, and EVERYTHING moves! So I can swap leads around all over the place, and the image on the monitor DOESN'T necessarily follow the physical port it's connected to What the hell? It makes testing things, or setting them up correctly, a real exercise in frustration. You end up with a pair of monitors suddenly and randomly mirroring a particular output, which wasn't the one EITHER of them were apparently connected to, another output no longer displaying on any monitor, and the remaining three moved around even though they weren't touched.

Very irritating.

So I either need to put the old cards back in and chalk it up to experience, or find a newer card that has the same or better performance than ones that are five years old, and spend yet more money

Any recommendations on graphics cards that actually work?

pca