What is the cheapest video card I can get with best performance for GPU rendering of Cycles?
Vista 32bit PC tower.
for a pc tower try an nvidea…you can pick them up from a best buy near you for around 90-200 dollars. They work really well.
Oh ok. Are there any features or chips I have to look for or are they all suitable for cycles?
Better to use most powerful single chip card with maximum onboard memory. Cycles support only one device, and scene related data must fit on onboard adapter memory. Double float precision not used, so you can skip that expensive top card feature.
You can get a used gtx260 on ebay for cheap. Its a pretty good card. For a little bit more you can get a new 440. They both work well in cycles and will be faster than your current processor, unless you have an 8 core intel extreme or something like that. The 260 is a gamer card while the 440 is more mainstream.
I will check them out, I was just looking at the specs on Wiki, and the 440 looks impressive but expensive.
Oh sorry, thanks.
Yeah, it all depends upon your existing RIG. Your main concern should be how powerful your power supply is. That will dictate what chip you can install. Also if your PCIe slot is 2.0 compliant is a factor as well. Once you know those two things choose the best fit by visiting the nVidia for spec comparison.
Hi,
I have been testing cycles on my home computer and I have been a bit disappointed by the GPU feature. In my case, GPU render is 10-20% slower than my (quad core) CPU.
I have been programming in cuda for about a year and usually, for calculation intensive (engineering type of) problems, I usually get a speed up of x60-x200 (depending on the complexity / memory requirements of the problem) compared to 1 CPU core (ON THE SAME MACHINE), so I was expecting roughly the same performance with cycles (x15-x50 compared to 4 parallelized CPU cores)! We are far from it.
I would be very interested in having some feedback from other users regarding the comparison between CPU and GPU.
All this to say that I would not put too high hopes and too much money on a new GPU just for cycles at the moment but I hope I can be proven wrong.
JPN
I´ve no idea what you’re doing wrong.
Either you don´t use the GPU feature properly, your GPU is slowass or your CPU is badass or both 
I tried a 820k poly scene just now. Building the BVH takes quite some time and is done on the CPU for both variants. Only the raytracing itself is done on the GPU.
CPU Q9550@3.6GHz: 00:04:30.30
GPU GTX470@750MHz: 00:00:51.86
And I guess you’ll not see x60-x200 because I assume there are plenty of device to host memory operations. If you run all on the device you get those fantastic numbers, for easy straight forward calculations.
As you code in CUDA I guess you know how slow it is to synch the host and device and do memory operations between them.
Thanks Atom, yes I see that the card burns as hot as an oven. Hmmm, additional cost of rendering. Should I wait for a cloud GPU solution? Is there such a thing, I guess it would be killed by internet bandwidth and make cycles interactive dog slow.
my gpu isextrememly fast. It plays skyrim with no problem in high graphic mode, with blender cycles running ;D…and only cost me 90 sdollars
Oh which one did you get Evil?
the Nvideo Geforce 430. at best buy it costs 90 dollars as its last years model so its on sale 
All right, I rendered a scene with a Tesla C2050 and there I saw a speedup of 7-8x compared to 4 CPU cores, while I usually get 60-80x / 1 CPU core for my own projects on this particular card (that includes memory transfers when the problem at hand makes it necessary of course). So it’s not bad there. I’m sure it can still be improved a bit though. Now, not everybody can afford this kind of card for personal use…
PS : the 10-20% slower card was indeed an old one (GeForce 9600 GT), but was still 100x faster than the CPU on that particular PC.
Cool Evil, just found that I could get a 430 for $60! I noticed that it uses a PCI-e2 but my old Geforce 7100 is just PCI-e. Would it still be compatible?
The GF430 is crap.
I am not going to proof it in depth, there are plenty of threads around already where I explained it all.
Just to paint it more colorful:
A Radeon 6750 would be twice as fast and costs 80 USD - not much use for Cycles, but you see how bad the price to performance ratio for the 460GT is.
A GTX560 would be 5 times faster and costs 180 USD - so if you calculate back the GTX430 should cost 35 USD.
A cheaper card might look tempting becaues of the price, but on the long shot you pay more for less performance and have to replace the card sooner.