Will-my-pc-run-Arma3? What cpu/gpu to get? What settings? What system specifications?

[Will-my-pc-run-Arma3? What cpu/gpu to get? What settings? What system specifications?]

I'm currently running this on my not-so-great rig of an i5-750 at 2.8ghz, in addition to my HD5850 and 12 gigs of RAM. I get a terrible framerate in any gameplay situation no matter the settings. I'm not expecting anything better, but I'm wondering if an upgrade to a 660Ti and a 3570K would let me run the game on high or ultra reliably.

[Low CPU utilization & Low FPS]

Me and my friend tried a coop mission yesterday (the daylight one, with respawns). It was running awesome, My settings were all maxed except shadows, motion blur and disabled anti alliasing (of any kind, I hate it, makes me think I need glasses when all edges are blurry). When beggining, I was getting about 25-60 fps, depending on a situation and direction I was looking. The problem started to appear slowly, fps went down, and after two hours I was running stable 15 fps, nothing I tried to improve it helped. It was weird, because graphics load howered between 15-25%, and cpu cores were all quite idling (25-50% each). So, after two hours, it was rather unplayable. Maybe the respawn system buffers a lot of something (although dead bodies and vehicles do disappear). My pc was the server.

specs: i5-750 @3,3ghz / 8GB DDR3-1600 @1450? cl8 / GTX560 OC playing on 1680x1050

I have the same processor and it runs at 3.67 ghz by default--did you downclock it? That actually gave me a slight FPS boost in ArmA II, but I didn't think to try it here.

Edit: I'm referring to the fact that you were able to get a good framerate at the beginning. I haven't achieved that yet.

[Low CPU utilization & Low FPS]

CPU: Intel i5 750 @ 2.8ghz

RAM: 12GB

GPU: HD5850

Monitor: 1280x1024

I get 5-25 FPS in the infantry showcase with every setting as low as possible (except for the traditional gotcha settings we all know and love). I've read that people with poorer machines have gotten fine performance, so I'm wondering if there are any tricks I'm missing.

Also, I intend to upgrade and I'm looking at a 660Ti and a i5-3570K, so if anyone has that setup it would be nice to know your performance.

[ArmA2 / OA (low) performance issues]

Hey guys. I have serious FPS issues in ArmA II, and was wondering if you have any advice. First of all, I'm running a Radeon HD 5850 and a quadcore i5-750 CPU (2.66 GHz). I meet the recommended requirements for ArmA II, but it runs like crap, even with all the graphics at their weird obscure "optimal" settings. It also runs the same on high settings. The weirdest part is that if I alt+tab for a second and then come back, it runs fine for a few seconds.

Someone was telling me that he fixed his issues (which were similar) by disabling hyper-threading, but online a lot of people are saying the problem with hyper-threading was fixed in the beta patch a long time ago. Plus, I can't figure out how to disable it anyway (can't find the option in my BIOS and the Task Manager method doesn't work because I don't have "authorization" or something like that.)

Again, I have the recommended specs (or fairly close anyway--processor is 2.66 while recommended is 2.8) and get a buttery smooth FPS for a few seconds after alt+tabbing, but it's otherwise awful!