@usher
Model numbers mean nothing in this case but specification means everything. A GTX580 with 3GB memory will outperform any of the cards you mentioned by a mile; in preview as well as rendering where applicable.

@ oldsmoke - i do appreciate and respect your advice and recommendations re 580, and agree with you entirely - but finding a new 580 is impossible here in aus, and i'm not interested in a s/h one, so i'm looking to move on...

i was very happy with my 560, and the 650 i have at present is ok, but as i originally wrote, the 560 is flakey, and the 650 nothing more than a temp measure.

so, to rephrase my question, what should i be looking for in a nvidia card to enhance PLAYBACK, i'm not in the least interested in rendering speeds. should it be, say, cuda cores as pointed out in jd's video?

if cores are the case, then would i be better off with a 760, rather than 750ti or 660ti as it has more cores or not enough to warrant the price diference?

Go with the Geforce GTX 960 later this month, or next month. Whenever they release it.

Leslie, I too have the GTX560. I'm interested in the symptoms you're getting for you to say that it is going "flakey"? It's something that I'd want to keep a weather-eye on. What's making you think it's going flakey?

Cheers

Grazie

i think on the little research i've done it looks like the 760 - though i'll wait and see how much they're asking for the 960, but i suspect it'll be more than i'm willing to pay. that said, the reason i asked here in the first place is i don't really understand what i'm researching ;-)

ah grazie, these things are sent to try us and remove what little hair we have left...

symptom a. blank screens after supposedly booting.

" b. bsod with some nvidia problem or other (not necessarily the same one every time)

" c. strange 'tearing' on some windows (in any program)

none of the above were regular, but enough for me to pull it out and get a cheap 650 till i know what i want.

as i wrote, a brand new 580 would be my first option, but that doesn't exist. AND, i need to be moving forward. as much as i love vegas i wont compromise my other programs because of it.

@usher

what should i be looking for in a nvidia card to enhance PLAYBACK

The problem with Nvidia is, and this has been discussed plenty in here, the Keppler GPU used in the 600 and 700 series is not well supported in Vegas. Nvidia has changed the architecture and focused on gamers and gamers only with the consumer line. However, the Keppler Quadro series isn't doing so well either with Vegas.

Nevertheless, this what you need to look out for: CUDA cores, memory, memory bandwidth and memory bus width.

If you look here http://en.wikipedia.org/wiki/List_of_Nvidia_graphics_processing_units#GeForce_500_Series the column "Config" is very important here and so are the memory columns. Now compare the GTX580 with the 560, 650. The 760 now looks very good on specs but it actually has less render output units compared to the 580. There are also articles on the Internet that will explain how CUDA cores are organized in the later models vs the 500 series and that more isn't any better.

We certainly have to wait and see how the 900 series will fair. How about an AMD/ATI card like a 280X or 290? Many here in the forums have great results with those.

When you identify the cards your interested in, go to EBay. The gamers out there change out their high end video cards as frequently as we change underwear. And since they know they are eventually going to upgrade, they keep their cards in good condition will all original packaging. You can usually get a great deal on any card a year old or more.

@oldsmoke - thanks for your time with that clear explanation, much appreciated indeed. i'll probably hang out and see what the 960 brings.
my inclination towards nvidia is based on my, admittedly long ago, experience of amd catalyst drivers - they were awful ;-( i presume this might have changed (i hope it has) since there's not much noise about them on the net. at my budget point what would you recommend?

@john222 - i do look on ebay, but usually only at new, i've always been wary of buying s/h electronics since i'm not too sure of returns policies, guarantees, etc. but your arguement makes sense. i'll see if i can build up enough courage to dive in ;-)

@usher

I bought both of my GTX580s off eBay and they both work fine. You can get a EVGA GTX580 with 3GB around $200.00 and that is usually cover with eBay Buyers Protection; I wouldn't worry too much. Look for one that has free shipping too.

Like you, I am not a fan of the Catalyst drivers but they seem fine now.

I buy and sell all my stuff on ebay, never had a problem. Take advantage of the fact that all electronic goods have terrible depreciation. I've even purchased all my CPU's and motherboards on ebay. It'a a great way to get a lot of bang for the buck. The only thing I buy new is hard drives.