New GPU 5750 or 5770?

[thereaper123]

Hello. I have a geforce 7900gs and I want to upgrade it with a new GPU. I don't have much money ( a bit more than 100 euros)
I already searched and found out that the 5770 would be the best, but I'm not sure if I can afford it.
My choices are these 4:
http://cgi.ebay.it/SAPPHIRE-TECHNOLOGY-Radeon-HD-5750-512-Mb-GDDR5-PCI-/140411155164?cmd=ViewItem&pt=Schede_video_per_PC_e_Server&hash=item20b12832dc

http://cgi.ebay.it/PIXMANIA-Radeon-HD-5750-1-GB-GDDR5-PCI-Express-2-0-/230491195635?cmd=ViewItem&pt=Schede_video_per_PC_e_Server&hash=item35aa5888f3

http://cgi.ebay.it/ws/eBayISAPI.dll?ViewItem&item=140411149971&ssPageName=STRK:MEWAX:IT

http://cgi.ebay.it/ws/eBayISAPI.dll?ViewItem&item=160408408957&ssPageName=STRK:MEWAX:IT

Is there a big difference bettween 512mb and 1gb? Is it better a 5750 with 1gb or a 5770 with 512mb?

Plus I found the 5830. I'm not really willing to buy it since it's more expensive and it consumes more power. But I'm asking just in case I can find one used for cheap. How well does the 5830 perform in crossfire in comparison with the 5770 in crossfire? What GPU can I use to crossfire it with? Only another 5830 or also another from the 58xx series?

If you have any other GPU (nvidia cards as well) to advise with similiar performance and price, advise it =)
I can already tell you that I'd rather buy a 57xx than a 48xx because of eyefinity and power consumption.

 

[Onus]

I'm not sure I'd risk buying a high-end component like a GPU on eBay.
Also, what brand and model of PSU do you have?

 

[thereaper123]

what is your monitor resolution? if you game at 1600x900 or below the 5750 is fine.

there is a bigger difference of 1GB to 512mb on the 5770, not as much on the 5750.

I use a 1080p monitor. I've never played with a reolution higher than 1600x900 because my 7900gs couldn't handle more, but it should be more than enough. I'm mostly looking forward ffxiv and guild wars 2, and as long as I can max them with the highest resolution that'd be more than enough for me.

I'm mostly looking forward the 5750 with 1gb and the 5770 with 512mb, and would like to know which one is better since the price is more or less the same. But if you guys say that the 5770 with 1gb is a lot better than those two, I could wait a bit and try to get more money.

I'm not sure I'd risk buying a high-end component like a GPU on eBay.
Also, what brand and model of PSU do you have?

I have a stock dell xps 410. It has a 375w psu if I remember well. I read of many people with a gts 250 on this pc, so I think a 57xx is fine. Plus I have only 2 HDDs and no more drives connected.
Iknow, ebay isn't the best to buy from, but here in Italy the price is 50%-100% higher in the shops, and I don't know any other online shop to buy from.

Just one more thing. Could the prices fall in the next 2 months? Since I'm buying the GPU mostly for ffxiv, I could wait till september.

 

[jyjjy]

The HD5770 512mb is a better card than the HD5750 1gb although the 1gb HD5770 would be optimal, especially for a 1920x1080 monitor.
A 375w Dell PSU should be fine for either.
I wouldn't count on the prices of the cards going down much in the next two months although it is possible, especially if the GTX 460 ends up being competitive. However considering you are using Ebay there are always different deals depending on when you look. 2 months is plenty of time to perhaps spot a 1gb HD5770 in your price range or get lucky on an auction for one.

 

[thereaper123]

Thanks for your replies. I'll try to get a 1gb 5770 then, and if within august I won't be able to buy one I'll just go with a 512mb one.
If possibile I have one more question. Between 2x5770 in crossfire and 5770+5750, is there a big difference?
I'd like to upgrade later buying a new mobo and another 57xx, and would like to know if there is much difference between those two combinations.

 

[jyjjy]

I believe when you crossfire 2 cards that aren't the same the better card essential operates as the weaker card. So crossfiring an HD5770 with an HD5750 is the same as just crossfiring 2 HD5750s.

 

[jyjjy]

Also I would definitely aim for the 1gb HD5770 if you want to crossfire in the future. When crossfiring the memory isn't added together but rather is redundant. 512mb is ok though not great for a single HD5770. In crossfire HD5770s will give you processing power similar to an HD5870 and 512mb will severely limit the effectiveness of that much processing power.

 

[thereaper123]

Also I would definitely aim for the 1gb HD5770 if you want to crossfire in the future. When crossfiring the memory isn't added together but rather is redundant. 512mb is ok though not great for a single HD5770. In crossfire HD5770s will give you processing power similar to an HD5870 and 512mb will severely limit the effectiveness of that much processing power.

I see. Gonna try to get the 1gb one in any way then. Thanks!

 

[Onus]

I'm hoping GW2 will run nicely on my single HD5770.