MTVU causing slowdown. Any reason why?

[Scuddie]

Most of the games I play get a decent benefit from the absolutely awesome MTVU hack. However, on Wipeout Fusion, it has the opposite effect. When running standard mVU1, the EE thread hangs around 90-95%, the GS thread is around 35-40%, and I get approximately 50 FPS on average.

When I use MTVU, the EE thread is now 75-80%, which is to be expected. However, the GS thread hops up to 50-65%, the VU thread is always at 100%, and I get 22 FPS on average (30 on rare occasions). What's worse, is that I'm having very noticeable SPS on distant objects. Enabling EE cycling and VU stealing have no effect.

I know certain games will crash or hang due to the way the threading works, but I'm not getting anything like that. I can play for a good two hours (with immaculate aim ) without a hitch. Everything is working as it should, just at a much slower pace.

So, with that said, is this a textbook example of diminishing returns, or is there likely to be a bug (or an unfinished speedhack)?

[recoder]

If you have a Dual-Core system, MTVU Hack might cause a slowdown.
MTVU Hack wants the VU to run on a seperate thread for which it needs a seperate Core if Possible. So on Dual-Core system, sometimes it will cause a slowdown.

[Scuddie]

I suppose I should have mentioned, I have a Q6600 @ 3.2GHz, 4GB Ram, and a 1GB 460GTX

[tuanming]

Not all games will benefit from the MTVU hack.

[Squall Leonhart]

[19:13] <Squall-Le> is Wipeout fusion one of the games that need that unsupported(with mtvu) ABORT sign
[19:14] <cotton> i think so
[19:14] <cotton> i don't have the game to check but
[19:14] <cotton> i think someone mentioned it

Thus MTVU won't be of any use in this game.