Which DX9c games? And at what settings? Of course the GeForce 7 isn't a total speed-demon for such - that's pretty cutting edge for it actually. It should be able to handle things like Half-Life 2 with HDR or Fallout 3, but asking it to do something like Skyrim or Mass Effect 3 is probably too much. But none of those games are "2004" - there's a reason Phil and others were suggesting GeForce 8 and such a few pages ago... 😊 The CPU is also a factor as you move towards 2010 - Pentium 4 (and even Athlon64) quickly become woefully inadequate as games started to want hardware multi-threading and higher performance.
For games from around 2004, like original Half-Life 2, CS:S, Unreal Tournament 2004, Tomb Raider: Angel of Darkness, Hitman: Contracts, etc the 7800GS/P4 combo should have no problems. Even later games like Oblivion, Doom 3, and Hitman: Blood Money should be playable, depending on what settings you'd like (I know 7900GS and 6800GT/Ultra run all of those). If you just want to run all games from 2002-2010 with everything at the absolute highest settings with crazy high AA at crazy high resolution, you will need a substantially more powerful machine. 😊
Cooler-wise, neither of my 7900GS or 7950GX2 cards really "need" the big Zalman - they run pretty cool with single-slot coolers like the 7800GS. They're pretty power efficient cards (even the big 7950GX2 is only specified to something like 140W max; the single-GPU cards are usually under 70W).
Also, out of curiosity, why do you keep calling Leadtek "Qleadtek"? 😊 😕