Cerb, I am pretty sure in no way is your 1gb of vram on the your gtx460 going to be your MAIN limitation like you claim. that gpu itself would hit a wall long before its 1gb of vram would be a problem.
Not when more than 1GB is trying to be used, which is not hard to do now, and will certainly only be easier in the future. I said all too often--IoW, I find I can get OK performance as far as my CPU goes, but there's only so much room to jack up textures, and when available as an option, visible distance. My
main limitation is my CPU.
900px vs. 1050px or 1080px is not enough to consider significantly different texture detail levels. 1440x900 will be much faster, but for a given level of IQ, nearly the same amount of RAM will be needed. If you only use a game's base presets (low/med/high/ultra/etc.), more GPU power and memory go hand-in-hand, but not necessarily if you go raising what brings the most IQ difference within reason. I think any really good GPU upgrade from a 4870 and GTX 260 would be overkill for 1440x900 in terms of GPU power, for the time being. AFAIK, the only game around to really warrant too much more of a GPU is Dirt 3, and even then only at max detail, which is more or less like saying Crysis demands it.
and you do realize the title of the thread? at 1440x900 there is zero point in him spending more money to have more than 1gb of vram on a gtx560.
I think a GTS 450, GTX 550, HD 5770, HD 6770, and HD 6790 could come up short, possibly not being as good as his GTX 260, depending on specifics (reviews with a GTX 260 and newer cards are not common, but what little I've seen has been impressive for the aging GTX 260). It's not so much that I think the OP needs a 560, but that I figure that upgrade will offer tessellation, and a very minor performance improvement beyond that. So, if it's going to happen, why not enable higher detail levels, and beautification mod options for SP games?
http://www.anandtech.com/bench/Product/170?vs=176
General edge to 4870, here.
http://www.anandtech.com/bench/Product/180?vs=176
Moderate improvement, and most will be 10% or more faster, due to factory OCs, but >$150 worth?
GTX 560 should generally be 30% or so better, but not in the AT bench selection.
http://www.anandtech.com/bench/Product/164?vs=176
Similar showing.
http://www.anandtech.com/bench/Product/162?vs=176
Quite a bit better...but, also notice how the gap tends to close in DX games at 1680x1050. The faster GPU's performance is somewhat wasted as the resolution lowers.
Now on 2011:
http://www.anandtech.com/bench/Product/304?vs=313
http://www.anandtech.com/bench/Product/304?vs=291
http://www.anandtech.com/bench/Product/304?vs=290
Much wasted, granted. What about cheaper?
http://www.anandtech.com/bench/Product/304?vs=316
http://www.anandtech.com/bench/Product/304?vs=296
No better.
The grain of salt to add to all of that? 1440x900 should be, when limited by the GPU, 30-40% faster than those 1680x1050 benches, and about 80% faster than the 1920x1200 ones. The games whose tests can slam those cards tend to be those that can slam most anything (good ol' Crysis, FI).
In all honesty, I think keeping the GTX 260 for a bit longer, taking advantage of nV's slightly CPU-hungry drivers, and a little boost here and there on the occasional TWIWMTBP game, would be the best short-term route
(kind of sad that proprietary game changes are my primary reason for thinking the GTX 260 over the HD 4870, but...). Then, once a few anticipated games come out, and/or 28nm GPUs, bite on a new card.
If the OP is set on upgrading (upgraditis symptoms can be overwhelming, you know!), a decent 2GB card will allow all eye candy to be turned up, handle more/prettier mods for SP games, and have some breathing room for longevity--neither of his current cards are remotely new, but neither are under-performers, and very little significantly under his budget will be too much of an improvement, save for the few DX11-only game options here and there, fewer watts at idle, and lower dBA at the OP's computer chair. At 1440x900, how much better will a GTX 560 1GB really be over a GTX 260 (I'm assuming 896MB--if less, the 4870 is 1GB), unless you could cram more textures in there, keeping a higher overall level of detail at any given time?
I personally think the OP's jaw will drop just from the new CPU, and that a GPU speed upgrade will likely be underwhelming, given how few pixels need pushing...but that if he wants a video card upgrade, best to really go for it, instead of getting meager/moderate speed improvements at a lower res, yet with nowhere to go when sharper become an option that will kill performance.