Created by Nick Herres somewhere around 2000, 2001.   Rendering of the Descent 3 Phoenix Intercepter done in Bryce3D.  Additional credit goes to Kumen who's 3DsMax model was used as a reference. 

http://www.visualarray.com/artwork/Phoenix.html

Copyright belongs to Nick Herres.

Key differences:

There's a 2-seater planned for the T-50;
The T-50 has a slightly larger (78.8 sq. m. against F-22's 78.04) and better-loaded (330 kg/sq. m. against 340, max. 470 vs. 487) wing, which makes it more agile in dogfight, combined with...
3D thrust-vectoring engines (Saturn Make 117 - no official name for the engines, they're still referred by development code) - the F-22's engines are 2D-vector only;
Improved radar signature, claimed to be smaller than F-22's (0.3-0.4 sq. m. in centimetre-range radar waves vs. F-22's 0.4-0.7);
Higher thrust:weight ratio (traditional for Russian fighters) - 1.19-1.38 combat-loaded, 0.84-0.97 max. weapons+fuel load/max. weapons load (1.17 combat/0.88 max. load for F-22);
Higher internal fuel load, 12500 kg., allowing the T-50 to work as a long-range interceptor with a high supersonic dash speed;
Higher maximum airspeed - 2100-2600 Km/h depending on altitude (most planes can actually go faster than their maximum rated airspeed, but at the risk of airframe damage);
Lighter than the F-22 (yes it's larger, but it also weighs less): 18500 kg. empty (F-22's 19820);
Higher max. G-load (10-11 g against 9.5 for the F-22).

If anything the performance is bound to be improved - the numbers are given for the T-50 prototype, not the production version (compare the T-10 with any Su-27 production variant).

Overall it's pretty similar, but the T-50 is designed to be an agile dogfighter with 3D thrust vectoring, a concept the USAF has forfeit. It has fully mobile fins (whole surfaces move, there're no rudders).

This is something that came up several years after PM was released. Turns out in the USSR there was an orbital interceptor project, "BOR". It was to be armed with radar-guided missiles for downing satellites and spacecraft in Earth's orbit. This is the BOR-4S aerodynamic mockup. Looks like Blackstar.

This is how GAME03 sounded in OPL3 format on the demo version of Descent.