Heres a good link to HyperThreading if anyones interested
But Beware as YOUR SERVER HARDWARE MUST SUPPORT THIS NEW Technology
and as Intel say
Performance will vary depending on the specific hardware and software you use. but could provide a performance increase in the neighborhood of 10-30%, depending on the application and the situation
If your really interested you could set up 2 test machines and try it but IMHO.... I think your barking up the wrong tree as far as Twin/Quad CPU Usage balancing is concerned.
As far as tips for improving database performance try
Higher Spec Hardware & more RAM,
Transaction file physically stored on a seperate Hard Disk away from the RAID Array of the Data File,
Tune Indexes & tweak sloppy Querys etc....etc...etc....etc...etc....etc...etc....etc. ..
"Everything should be made as simple as possible, but not simpler." - Albert Einstein
"Everything should be made as complex as possible, so I look Cleverer." - Application Developer