Why do the GTX 260 and the Radeon HD 4890 go for the same price?

You are right, the 4890 is superior. The prices are like that because AMD likes to stay competitive with their price/performance ratio. it actually will make them more money if they keep it at mainstream prices. thats really where the market lies...

anyways, back to your question, you can run a 4890 on that mobo but that will mean no crossfire. In this case, the GTX260 would be the better choice due to SLI capability.

What is a 1280x1024 motherboard? you mean monitor? if so yes, the card is overkill

Hm. Well since SLi costs a hell of a lot more money than I have at the moment, I'll probably end up getting the 4890.

Would it end up hurting my computer due to being overkill, or would it just be extra?

It is overkill but it will also be extra. You may think of getting a new monitor instead and a 4850 or something similar.

The 4890 is not overkill for this resolution.

Part of the reason nVidia is more expensive is that their gpu's are physically larger .

The 448bit vs 256 bit is misleading . Its a measure of memory bandwidth and since the 4890 uses quad rate memory then its effective bandwidth would be the same as 512 mb DDR3 .
The stream processors is also not that comparable . nVidia use less that can do more things , ATI use more that can individually do less

Not really as important as the results , which is , as you know that the 4890 is a much stronger card

The 4890 is over kill for a 19 inch monitor

It's overkill now, but it might extend the life of it.

Just to add to the OP:

The stream processing units are not directly comparable.
Nvidia uses vector units while ATI uses only scalar units.

When comparing bandwidth, a larger bus is usually seen as faster/better, but in the case, the ram is much faster, twice as fast in fact.
Liken it to a hose. i is 1 inch in diameter, the other is 1 1/2 inch in diameter. Even tho the 1 1/2 is larger, the water in the 1 inch hose is moving twice as fast, so ultimately the 1 inch hose puts out more water

The 4870 is like 4% better than the gtx 260 and I got mine for $123 on ebay and the gtx 260 was going for like $150-$160 so if you want something about as good as the gtx 260 go for the radeon 4970!  

Heh, well actually the 1.5 diameter hose is still more flow   Area is squared   hehehe

At any rate.. 4890 is a wonderful card. However, at that resolution it you would be fine with something like a 4850, and save some money..

To michaelmk86, I'm glad you have no problem spending someone elses money... While one is free to define "overkill" for themselves, there is absolutely no point in blowing the cash on something you don't need, the monthly best card for the money article here at toms gives you a good idea what is ideal for what price point and what resolution.. You will see they rarely advice more than a 4670 for that resolution.. there is a reason for this, once you have playable framerates more is a pointless money sink.. as well as you start to get into cpu limitations.

The 4890 is not overkill for this resolution if you want to play games like (Cryostasis, empire total war, crysis, crysis warhead, stalker clear sky, farcry 2, Tom Clancy’s H.A.W.X., arma2)try to play this games(with max setting ,4xAA, good frame rates) with the 4850…

Point well taken, heheh. I was underpowered when I typed that (low on coffee)

AND the GTX 260 costs more to produce than the 4890, its kind of sad really.

Sigh...

A 4850 is plenty for that resolution. Even with AA pumped rather high.. Crysis is the only example you give where high AA might tax a lower end card but the game is not optimized worth crap.

http://www.guru3d.com/article/ati-radeon-hd-4770-review...

There is a good set of benches for many of the games you mention..

How exactly do you define overkill?... yes, a 4890 gets more fps than a 4850 in those games.. so does a triple 285 SLI or 4890 crossfire rig.. So the op should blow a grand on his graphics? All he needs is something akin to a 4850.. anything more is of questionable value.. It is not up to me to spend his money though, if he wants to go as high as a 4890 then he can.. but why spend double the cash on something you would have trouble noticing? He should understand though, that his resolution is very mainstream.. thus a mainstream card is plenty, unless he is in the habit of buying things he does not need.

If one is picky about fps then fine, buy a super expensive card.. but for 99% of people a lower end card is fine, one should know if they are picky or not, and they can freely upgrade their choice based on that.

You know that the 4850 is not enough for this resolution and you keep talking nonsense.

I can't even be bothered replying anymore to this type of post.

@ Instrumentalist: Given the rest of your specs the HD4890 is a good match.
The 'problem' now seems to be the HD4890 is getting stupidly cheap, I've found one in the UK for under 140 pounds, which is in the same price range as the lesser HD4870/GTX260, why get a lesser card for your money? Besides, you may decide to treat yourself to a larger display, in which case the card will have the performance to drive it, ready and waiting to be tapped;)

Where are you and do you have a list of sites to check?
The best advice is the oldest: Check around, do not forget to add shipping and taxes when comparing prices and wait until the weekend for thos tasty 'specials' to crop up.

I've decided to wait until DX11 comes out.
If I don't like the DX11 cards, or they are too expensive, or whatever,
I can get a card like this for half of today's price.