Re: TK025 Dual Graphics Riser for T7400 in Dell Precision 690 ?
I'm quite familiar with the line of 54xx CPUs, I keep a running tally of 'best value' based on the % gains over the e5405's I have installed in the Poweredge. my calcs show the L5420, while only giving 25% in perofrmance gains over the e5405, does so at only $3 per % increase. My CPU utilization won't typically run more than probably 25%, so anything over 3.0ghz is probably overkill...which is perfectly awesome. That said, I like the fact that the L54xx CPUs draw less power and are a little cheaper to operate. (I know, it's a PE2900...but every bit helps).
The only thing to consider is if you're ever going to do virtualization, the Xeon 54xx have intel's virtualization, but do not have second level address translation (SLAT). It's not a concern unless you plan to play with virtulaization, but worth noting before dropping $500+ on upgraded CPUs. Note SLAT doesn't appear until the Nehalem family (possibly 55xx & newer), so it wouldn't work with the 54xx LGA-771 socket. Not sure of the 'true gains' because I can't test it, but it is my general (and likely misguided) understanding that SLAT will allow for the VMs to use the graphics hardware installed in the machine to improve performance versus using virtualized video card drivers. I'm not positive though...