Yeah but he will get much less for his existing kit as well if he waits. It's all pro rata and there are bargains to be had already
I just sold my AMD 4200+ dual core socket 939, dfi expert board and corsair 2 x 1gb memory plus coolermaster aquagate watercooled setup (pants really
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) for £200 in total.
I picked up the following:
Q6600 VID 2.5v 2nd hand
2 x 2gb corsair 6400 4-4-4-12 ddr2 new
ABit ip35pro 2nd hand
various 2nd hand watercooling including swiftech d5 pump, danger den cpu block (not the best but cheap), double rad, 4 x xilence fans, reservoir, tubing, rad mount, fuzion gpu block for my g92 gts, ram heatsinks (new)
total spend £385.00
Total upgrade cost only £185. To be fair it would have been less but for the extra cost of going from 2gb to 4gb and water cooling the graphics card. Without those it would have only cost me approx £100 to upgrade.
I was tempted to wait but then I never would have got £200 for my old setup so would probably cost about the same to upgrade.
So if I was the op, I'd upgrade everything except maybe the gfx as new ones out next month and will make little difference to the 2nd value of the 7800gtx.
As far as cpu limited goes, then yes you would be if you had a better graphics card.
Going from my 4200+ x2 running at 3ghz to the Q6600 running at 3Ghz (graphics card the same) I gained 5000 points in 3dmark06 and 11 fps (from 38 to 49 at 1280 x 1024 on high) in Crysis so the cpu was obviously holding me back and yours at 2.2Ghz would be even more so.