upgrade when you feel you're not getting the performance you want out of your card. my last (enthusiast) card was an 8800GTS G80 (5 years and still going strong)

Firebird-5

Still using the same card here. Play all the games at 1920 x 1080 with no issues. Most games with some AA and AF on.

Never really knew the point in releasing the 9000 series and 200 series was in the first place except to make more money.

It sure didnt take long for them to bring out the 400 and 500 series which looking at their performance benchmarks shows they might as well have just stopped at the 400 series.

Hearing the news about the 28nm Keplers (600 series) and their theory on the Maxwell cores I know to just wait until a real nice series upgrade comes out with the 28nm GPU change.

Heres a quote on approximate specs:

MODEL___SKU___SP___ROP__core_ CCLK__SCLK___M__blend__TMU__bus__Mtype__Mcap___TDP____Price
GTX690_GK100__32_*_24_=_768__ 825/__1650/_4600__72____96__512__GDDR5/ 2.00GB_270W__499 U.S. dollars
GTX680_GK100__32_*_22_=_704__ 750/__1500/_4200__66____88__448__GDDR5/ 2.00GB_230W__399 U.S. dollars
GTX670_GK104__48_*_12_=_576__ 825/__1700/_4600__48____96__384__GDDR5/ 1.50GB_190W__299 dollars
GTX660_GK104__48_*_11_=_528__ 725/__1450/_4200__44____88__320__GDDR5/ 1.25GB_155W__229 U.S. dollars = £141 approx
GTX655_GK104__48_*_10_=_576__ 650/__1300/_4000__40____80__256__GDDR5/ 1.00GB_130W__189 U.S. dollars
GTS650_GK106__48_*_6__=_288__ 800/__1600/_4600__24____48__256__GDDR5/ 1.00GB_105W__149 dollars
GTS640_GK106__48_*_5__=_240__ 700/__1400/_4200__20____40__192__GDDR5/ 1.00GB__80W__119 U.S. dollars
GT630__GK108__48_*_3__=_144__ 750/__1500/_2000__12____24__128__GDDR3/ 1.00GB__60W__89 U.S. dollars
GT620__GK108__48_*_2__=_96___ 700/__1400/_2000___8____16__128__GDDR3/ 1.00GB__45W__69 U.S. dollars
GT610__GK108__48_*_1__=_48___ 700/__1400/_2000___4_____8___64__GDDR3/ 1.00GB__30W__59 U.S. dollars

Looking at this I would go for a GTX660 not too power hungry and value for money. Dont think the 2GB mem cap is correct as we know the GTX590 have 3GB.

The overal performance you get still depends on what the bottleneck is in your system. Most of the time it is your CPU but could also be your HDD.

Its very suprising the extra performance you get out of your games when upgrading your CPU which I did from an 4600 dual core to a Q9300@2.5GHz 6MB quad. For the high end i7 or i5 you will need to look into running your games on the new SSD drives but ofc their price per GB are very expensive compared to the standard sata II and III drives. Around £200 just for a 120GB SSD!