Earlier this week i picked up a XFX HD 4890 to replace my EVGA 8800 GTS 512 G92. After playing around with it a bit it doesn't seem like there is much, if any, improvement. Some games like TF2 have seemed to taken a hit in performance, dipping down to 20-30fps. Crysis runs 30-high 40's on medium settings and no AA. The Witcher runs about the same on max details and no AA.
Any ideas on what could be the cause? Perhaps maybe a bottleneck somewhere? PSU not strong enough?
I didn't think this card would be running Crysis max or anything, but I was hoping for a bit better results then this.
CPU - AMD 7850 2.8 Kuma BE
4 gigs of GSkill 1066 Ram
Antec Earthwatts 500w with 2 +12 rails running at 22amps
Have you verified that you have the very latest ATI Drivers? The 4890 should be better than that, especially with that resolution. I guess another thing to check is to make sure you have as much power for that card as possible, so I would suggest trying to get as much of the system as you can on the opposite 12V rail from the GPU, and try to have ONLY the GPU on one 12V rail.
Routing your power comes down to knowing which connectors on your PSU come from which 12V Rail, and then trying to be creative. I guess since I have a modular supply I can do that easier, but with a non-modular supply you may not have too much of a choice...
I had upgraded from a highly OCed 8800GTS to a 4870 and i was really upset that I did not see much, if any improvement. Some games seems to run better on my OCed 8800. I did OC the 4870 and got some better performance, but the upgrade was pretty minimal. Since a 4890 is sort of a revamped 4870 with higher clocks, I would expect similar and this does not surprise me. If the game favors Nvidia cards, you will be even more upset.
I wouldn't worry about trying the 4 to 6 pin adapters. Have you run a benchmark of any kind? If not I would suggest your try 3dMark Vantage trial and see what your score looks like. If your score is fine in that, its gotta be some sort of setting or something with the games you are playing. If your score is lower than expected, then you may have a bad card, or some other problem.
4890 OC'd to 910MHZ/4400MHZ works at 1920X1080 with very high settings & 2X AA at 26FPS avg according to inbuilt benchmark in crysis. YES , PSU matters also bottleneck can be due to the slot being PCI-X 2X or 1X. pls make sure the game has the latest patch as well i am sure the ati drivers are updated. try using FRAPS latest version inbuilt benchmark in games give more effective results.