If I don't need Quadro, should I just get the XPS 15?

E7470 also has a hugely weaker processor -- it used the U-series dual cores, vs. the H-series quad cores on all models of the M5510 and most models of the XPS 15 9550 (ISTR the lowest XPS 15 is a i3-6100H, which is an odd duck of a CPU -- dual core, non-turbo'ed H-series, kind of the worst of both worlds -- no faster than the lowest-end U-series i5, and with worse power usage.)

As John noted, there's also a pretty big difference in the screen size, and in the quality of the screens.

The E5470 is available with quad core H-series processors, although they're downrated from 45W to 35W and a little slower -- still hugely faster than the M5510. In practice, I'm perfectly happy with the CPU performance of my E5470 as compared to my work-provided M5510. The screen is much nicer (with a much nicer peak brightness) on the M5510 -- I have the FHD in both, not the UHD on the M5510. The keyboard is also much better on the E5470, and the third regular USB and real ethernet are both handy.

I haven't used the E5570 enough to give an extensive personal impression, but the E5570 or M3510 are also worth looking at (they're basically the same machine, differing just in GPU model.) I don't remember for sure whether they downrate the CPUs to 35W like they do in the E5470 (I think someone said on the owner's thread) and they've got the off-center keyboard with number pad (a plus for some, I hate it), and they're a bit bulkier than the M5510. Some very nice deals on them on Outlet, though.

For SW development, it might also be worth looking at the M7510. Even bulkier than the E5570, but it's expandable to 64GB of RAM, which may be a big plus on a machine if kept more than a couple of years.

 

I presume you mean "faster than the E7470".

My understanding is that quad core being hugely faster than dual core requires having a workload which is more than two threads running at 100% utilization. If the workload is just a single threaded task with various background processes then the performance difference is small (assuming the same RAM and SSD). I've actually disabled hyperthreading for the i7-6820HQ on my M5510 because I rarely load all 4 cores. A test using wPrime running 4 threads revealed that 4 cores without hyperthreading actually ran a little faster than on 4 cores with hyperthreading! (I need to recheck this).

John

 

Yes, sorry -- still hugely faster than the 7470. The M5510 i7-6820HQ is modestly faster than the E5470 with the same processor.

To see a huge difference, yes, you need to be using all 4 cores; that doesn't need to be at 100% -- context switches are expensive, and many threads each starting and stopping for about a ~50% duty cycle on 4 cores are going to be quite a bit faster than the same number of threads on 2 cores, even if they'd still be within the theoretical 100% duty cycle on two cores. Comparing comparable models, they also have twice the L3 cache (and in practice, the best value dual-core CPUs are the i5s, so comparing to the i7-6820HQ it's 2.6x the L3 cache) and perhaps most importantly, a much higher thermal envelope. A dual-core U processor can run at max turbo on one core, and slows down with both cores at 100%; the slowdown for a second core at 100% is much smaller on the H-series processor whether dual or quad core.

I've been very pleased with my home desktop, which is a i5-6600K. OTOH, my typical workload involves one heavy IDE process (1 core heavily used, plus occasionally bursting to more) and a whole ton (around a dozen) services running in docker containers... plus the need for as much CPU as I can get my hands on a couple times an hour for compilation. I've tried to talk my work into getting me a 6-8 core workstation desktop, without much luck.

I haven't benchmarked HT vs. non-HT, but even if the very CPU-heavy compilation suffers a little because of it, speeding up the heavily multithreaded parts of my workload make it worth keeping on (at least until/unless they get a way to turn it on and off on the fly in software without rebooting.)