Windows 7 - lags in game

Hey how's it going everyone.
I have a quick question. I want to up grade my video card, but don't want to change the processor or anything else. Like i want to upgrade the card that sit fits my system specs, not sure if you get me.
My system spec.
Windows 7 professional 64bit
AMD Athlon 64x2 Dual core Processor 5400+
5G ram / ATi Radeon HD 4650 1G
480W power supply

If you can get your hands on a 5850 that would be a good buy, they basically sold them out and never restocked when they released the 6950 so it might be a bit hard to find. My specs are very similar though and it's what I'm using I have no complaints. I think going anything higher is just going to lead to some really annoying bottlenecks. Plus I've played everything in 1080p so I'm happy with it.
Then again it may also be among the best choices given your power supply.

I don't really know which nvidia would be it's equivalent though.
If price is not a problem by all means go with a 4xx series nvidia.
I honestly don't see the point in going to the absolute newest model card from either company as you'll still be suffering from some drive lag anyhow (newer games just don't precache...)

someone else on facebook said i could get a ati 5750 and i would be fine.
so basically i can get anything else that's close to 5850?

Well I would specifically suggest a 5850, the 57xx models are lower in price but you're going to get some choking trying to run in hd resolutions in newer stuff. To be honest at 1080p the 5850 just barely cuts it. (in dx11 stuff the older stuff no probs)

If that's just not in your budget get the highest spec 57xx you can afford.

i'm just dont want to lag in games.
like in BF2 i lag, so like i said just want the perfect card that can play in mid setting don't care for high settings, get me?

what about a ATI Radeon HD 5670?

BF2 should be running fine on what you have.
BF3 on the other hand...
Sorry I'll just drop out of the conversation now, but I was always of the mind that upgrading was an attempt to provide a bit of future proofing to a machine.

BF2 lags on my pc.
i guess ill wait till someone else can help

5850 may be hard to find.

But the nvidia equivalent may be the .. GTX 460?
Its close, but the 5850 is slightly faster.

But being as these cards are in the $180-$190 range .. you may be just as well off getting the GTX 560 if you go Nvidia for the same price or close to.
it will depend on what brand name you want to go with.

The 460 and 560 reccomend a 450W PSU with 24amps.

Does your antivirus program have a resident scanner?
If so, temporarily disable it, to see if game play improves.