Guess what I currently have in my Lian-Li case from 2005?
ASUS x79 Deluxe (the newer one)
XEON 1680v2 (8-core, 16 thread with 25MB L3 cache)
EVGA Geforce RTX 2080
Sound Blaster ZxR
Lost of storage.
The system that goes into that snail case should reflect the snail shape... basically the slowest hardware available new in 2005. Older stuff that was on clearance from previous years is even a better match. 😁
Since you said fastest before 2010, then go all out and make it fast. The Core i7-975 is going to be the fastest desktop CPU released in 2009 so go with an LGA 1366 setup.
http://www.cpu-world.com/Releases/Deskt ... 2009).html
Make sure to get at least DDR3-2000 and if not overclocking the CPU (a real shame to not overclock this setup), then at least run the RAM at a higher speed. The system will be a lot better with the RAM at DDR3-1600 or higher. Some games that were newer in that period need the higher throughput and lower latency for the RAM or eles they are a stuttery mess.
Edit:
Fastest single card GPU - AMD HD5970 (use two of them for quad crossfire).
Add an Nvidia GTX280 for PhysX.
You can run a Hybrid setup that will use your AMD cards for rendering and the Nvidia card for PhysX.