When considering an upgrade I can stay with my current AGP mb or a new PCI-E board. For example a ATI X1950PRO exists in otherwise identical forms in both AGP and PCIe version. So I wonder how much difference in performence makes AGP vs PCIe?

You can really do that on your present Mother Board? Wow...Well, in answer to your question, the PCI-E ('E' for 'enhanced') is the better way. This interface has much higher through-put bandwidth.That alone seals it in the bag.PCI-E if you don't have to upgrade anything else, because you hoped not to. If you DO have to/want to get a new M.B....then PCI-E all the way.Cheers!Mitch

I think some cards may have the same name but differing specifications in PCI-E and AGP formats, that aside if the cards are equal I do not think PCI pulls ahead of AGP untill one gets to the highest level cards. Furthermore whilst many people presumably bought PCI cards for their 16 potential [ as opposed to AGP 8 ], many people fitted them in pairs to restricted SLI motherboards which allowed 16 when one Graphics card was fitted, but changed to 8 + 8 with two graphics cards.http://en.wikipedia.org/wiki/PCI_ExpressBest and Warm RegardsAdrian Wainer

AGP 8x max transfer 2gb/secPCI-E max transfer 16gb/secPCI-E v3.0 max transfer (even faster)However...I read...and someone correct me if I am off here...where video cards don't get near these max throughputs and therefore the difference between AGP and PCI-E, so far, has been negligible.Now, going forward, it might matter more because cards will be capable of using more of that bandwidth.So in answer to your question: not much now but gradually more as we go forward.RhettAMD 3700+ (@2585 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2gb Corsair XMS 3-3-3-8 (1T), WD 150 gig 10000rpm Raptor, WD 250gig 7200rpm SATA2, Seagate 120gb 5400 rpm external HD, CoolerMaster Praetorian

>PCI-E if you don't have to upgrade anything else, because you>hoped not to. If you DO have to/want to get a new M.B....then>PCI-E all the way.>But my current mb is S939 and I would need new CPU RAM Videocard and PSU which would cost about the same as that big TFT monitor you have been writing about.

>AGP 8x max transfer 2gb/secI had problems with a game and AGP 8x so I used AGP 4x instead. I didn't noticed any difference in performence. Just like overclocking my current AMD 64 3200+ to 2.2 GHz turning it into 3500+.>So in answer to your question: not much now but gradually>more as we go forward.>Important thing is the current situation since I comsider what to do within about a month or so.

Rhett's got it. AGP and PCI-e are just busses. Consider the buss the racetrack. The GPUs (6600GT, 8800GTS, etc) are the race cars. We are just now getting "cars" (the 8800GTX) that actually need the speed capability the old AGP "track" (buss) has been offering for years. These buss upgrade cycles: 1) Vcard's AGP to PCI-e to PCI-e 2.0, 2) Harddrive's UltraATA 100 to 133 to SATA I to SATA II, 3) Mobo's 533mhz FSB to 800mhz FSB to 1066mhz FSB have been total hype, designed to sell useless capability to an under-informed customer base. I say, Shame on them.

>I think some cards may have the same name but differing>specifications in PCI-E and AGP formats, that aside if theHere are some specifications forSAPPHIRE RADEON X1950PRO 512MB 2XDVI DUALLINK AGPRAMDAC 2*400 MHzGPU core clock 580 MHzMemory speed 1.4 GHzthe same forSAPPHIRE RADEON X1950PRO 512MB HDTV PCI-ERAMDAC 400 MHzGPU core clock 580 MHzMemory speed 1.4 GHz>cards are equal I do not think PCI pulls ahead of AGP untill>one gets to the highest level cards. Furthermore whilst manyand the X1950PRO is not among the highest level cards