I'm trying to upgrade a computer I've bought nearly 5 years ago. I've been upgrading more and more to it lately, my first ever upgrade was replacing 512gb of ram with 2gbx2 (1066mhz-ddr2). Later on I've added a second hdd making it 360gb, as well as buying a new monitor from my old 17" to a 20" ASUS. Anyways, I have never upgraded my cpu, it's an old athlon 3800+ clocked at 2.4ghz. I wanted to buy a 4670 since my 8400 broke a few months ago, but I'm unsure if I'll get a huge bottleneck where as it won't be worth it. The games I play and hope to play when I get it is;
~ Starcraft 2 (med-high settings at 1280x720)
~ FEAR 2 (high settings 1280x720)
~ Half Life 2 ep.2 (Max settings 1280x720)
~ Just Cause 2 (Med-High settings, no aa, 1280x720)
There are more games, but as long as I can play anything on med-high settings and at a resolution of 1280x720 I would be happy.
Too put it in old money a 4670 will perform around a 1950 Pro used to, if you understand that ? Will the CPU hold it back well probably yes i would think so. Lets be sure we have the right model first are you talking about the 64 X2 version ? There was a single core 64 3800 but i think if i remember correctly that was clocked higher than your stated speed which has me thinking its the X2 model we are talking about here.
Either way its pretty close as todays games would swing things in favour of the X2 over the single core CPU anyway.
The way it works is that the CPU will have a speed which it cant go over when its providing the GPU the info to draw the scene, this top speed is esentially where your restriction will be. Its not a bottleneck as such but its how everyone refers to it so we wont get into that can of worms.
I would expect that you will find that the restriction isnt really noticable to you and you will get a better experiance out of the card. Any GPU power that you loose in FPS terms due to the restriction can be unlocked in the form of image/quality improvements anyway, higher AA/AF and ingame settings before performance starts to drop off.
We pretty much recomended these cards to everyone with old p4 rigs a year or so ago and your CPU is a touch above that so you should be good to go as far as im concerned.
FEAR might be a little hard to achieve max settings on, though your resolution is indeed quite small. Actually, considering you have one of the key components for an upgrade (RAM), you could really spend $40 on an mATX mobo and $60 for an athlon ii x2 CPU. That, and an HD5670 (54 watts max, IIRC).