Latitude E6420 advice, 2720QM or 2620M?

Hi all,
I'm placing an order this afternoon for both a E6420 and a E6520 and could use some guidance on the processor choice.
The only really heavy loads on these laptops will be VMWare Workstation. I conduct sales demos on VMs and need the VM to perform well.
I'd bet that the quad core will do better running 2 or more VMs, but assuming I am only running a single VM and not doing anything processor-heavy on the host OS at the same time, which processor is likely to perform better for me?
Will the 2.7ghz dual outperform a quad running at 2.2ghz hosting a single VM?
Thanks,
Walter

 

Notebookcheck's CPU benchmark table shows that the 2720QM is slightly faster than the 2620M for single-threaded applications (Cinebench single, SuperPi). This is probably the result of the bigger cache more than offsetting the maximum CPU speed.

John

 

Thanks. That's the kind of info I was looking for!

 

It's probably the bigger shared L3 cache, but there's also probably some slightly better binning making for higher thermal headroom for turbo. In theory, both can do up to 3.2ghz/32x with 2 cores active, and for heavily-single-threaded stuff the amount of time the 2620M can actually do the full 3.4ghz/34x (vs 3.3ghz/33x on the 2720QM) may be limited.

As for the original question, VMWare Workstation tends to use a bunch of its own CPU, so if the application within the VM itself can take advantage of more than one core (even if it's fine on a dual) you may see some additional advantage of a quad-core. If the application within the VM is largely single-threaded, then nevermind

 

Thanks. The biggest consumer in the VM is Oracle database. And then an application layer and web server. I generally set the VMs up as dual core.

 

The 2620M is barely faster than whats available on the e6410/e6510. I'd absolutely get the 2720QM if your going to get a e6420/e6520.

 

Thanks everybody. I figured I could make the boss a little happier by saving a couple hundred bucks on the new laptop, but it looks like the 2720QM is the ticket.

 

Also, if you were to not get the 2720QM, you'd probably be better off with an i5 because I don't believe the 2620M is all that much better than the i5's.

Be sure to get the 1600x900 display though, that's the most important upgrade

 

Oh yeah, the 1600x900 display is definitely on the list. The laptops have STILL not been ordered... hopefully Mon.
Maybe that will be enough time for Dell to work out the quality issues and give me a laptop that does not pop apart when it is handled!