Most currently popular games (Black Ops, BFBC2, Starcraft 2, Mass Effect 2, Mafia 2, etc) would be problematic on a stock 4870 and E5200 config, running the typical 2 or 4gb ddr2 that such a system would be running, at a common 1680x1050 or 1920x1080 display. Max details/settings on any of those games would choke that system way below 60fps average, with possible single-digit minimums in certain situations.
That's not to say one couldn't tweak the settings to look pretty good, and make the thing pretty playable, but all details/settings maxed out? No way. There are many games that are chuggy on full-blown 5870/GTX460 level cards at 1920x1080 unless you back things down a bit. Go try Metro 2033 on a 4870 w/5200 at 1920x1080 at max settings and have fun lol. Overclocking the 5200 to ~3.4ghz or so would help a bit of course.
But yeah, Toyota is correct. It's true that a lot of older titles can do max settings with that config, but basically all popular games released in the past 12 months outside of possibly New Vegas, would be chuggy maxed out.