I´ve an ATi 4770 512 MB, and I´m planning to buy a new 24 " Screen, so I would like to play at high resolutions 1920 x1200.
I´ve seen a great offer a new 5850 for just 110 €, so I was thinking in buying it (it´s cheaper than a 5770¡¡¡)
My system specs are:
Pentium E 5700 (Bottleneck???)
4 GB RAM
Silverstone Strider Essential 500 W
I would doubt that it's cheaper than 5770, but if you found 1, why not to get 1 if you want... yeah! good question about bottleneck! I think it will bottleneck the GPU! and btw, your PSU is minimum requirement for 5850... I would upgrade the CPU and PSU before getting the 5850!!
Is that secondhand? That's a sweet deal either way, just make sure there's nothing wrong with it.
You'll probably be upgrading to a 1080p screen. In that case, the 5850 is a good performer at that resolution, allowing you to crank up the settings and add a bit of AA.
Your CPU will definitely bottleneck your GPU, even at high resolutions. If you don't want to upgrade yet, try overclocking instead. As for your PSU, as long as you have the requisite 2x6-pin PCI-e power connectors, it's OK. The TDP of the 5850 is 151 watts, and I doubt that the rest of your system consumes 350W.