macro-ops fusion in Core 2 Duo/Quad

[PeteRoy]

I didn't know macro-ops fusion doesn't work in 64bit until I read this, does it mean that 64bit Vista should be slower with Core 2 Duo than 32bit Vista on the same machine?

Until now all I heard is people say how much faster 64bit Vista is.

I still use Pentium 4 and now I'm happier I waited for Nehalem because it will support macro ops fusion in 64bit as well as 32bit.

 

[myocardia]

Originally posted by: PeteRoy
does it mean that 64bit Vista should be slower with Core 2 Duo than 32bit Vista on the same machine?

No, it only means that it's lead over an Athlon X2 isn't as great in 64-bit mode. BTW, macro ops fusion doesn't add much performance. I believe it only adds 2-3%, at the most. Your P4 is still miles behind the C2D's.

 

[aka1nas]

Wasn't this changed with Penryn? I thought it was only an issue with Conroe.

 

[jones377]

Originally posted by: aka1nas
Wasn't this changed with Penryn? I thought it was only an issue with Conroe.

No, it's "fixed" and expanded in Nehakem only.