Question about Core 2 Quad and i7 quads

Doesn't Core 2 Quad have all 4 cores running higher than the i7 quads? Or am I just uninformed?

 

Yes and no. Depends on the specific Core 2, Nehalem, and/or Sandy bridge processors you are talking about.

 

Well the Q9000 and Q9100 are both faster than first gen i7 like the 720, 820, and perhaps the 920

 

Which i7 quads? The Clarksfield quads, yes, the Sandy Bridge quads, no. The latter Turbo Boost by a lot even with all 4 cores active.

 

I mean the Clarksfield quads.

Was the point of the Clarksfield quads for higher performance in single threaded apps?

 

Also keep in mind that you cannot determine CPU performance by comparing clock speeds of two processors across different CPU architectures.

A Clarksfield or Sandy Bridge CPU is going to be significantly faster than a Core 2 generation CPU on a clock-for-clock basis. You really need to use a CPU benchmarking tool (and not just look at clock speeds) in order to compare relative performance.

 

The widely accepted number is that i7 is about 20% better than C2D clock for clock, so the i7-720QM at 1.6 GHz (effectively 1.9) is roughly comparable to the Q9000 (2 GHz), and the i7-820QM at 1.73 GHz (effectively 2.07) is a little better than the Q9000, but slightly under the Q9100 (at 2.27 GHz). This is only for a straight clock comparison, though. If you add in turboboost, the i7s pull slightly ahead (on all 4 cores... even more so with fewer than 3 cores). As well, there's hyperthreading, which advances the Clarksfield chips a little more. Basically, the i7-720QM is a fair match for the Q9000 and the i7-820QM is a fair match for the Q9100 when all cores are fully in use, and better performers when you're using less than all 4 cores.

 

Please remember that the Core 2 Quad chips were aimed at a higher market segment, priced higher, and rarer than the lower end Core i7 processors, so you can't really make direct comparisons about how some of the Core 2 processors were even with or maybe even better than the i7 processors. The 720QM is pretty much dead even with a Q9000 most of the time, taking a lead by a little bit only when doing heavy number crunching type work or in the rare times when being pegged on only one or two cores. On the higher end, the same that applies between the Q9000 and 720QM applies to the 920XM and QX9300. Only the 940XM is really any better than a QX9300, and then not by much.

 

This also holds for the dual cores. I am sure Core 2 Duo T9900 is way better than most of the Core i3 and i5 chips. However the former was top-of-the-line whereas the latter were entry or mid level chips.


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More or less. Clarksfield was a stop-gap measure: Intel needed to somehow stuff the 130W Nehalem CPUs into a 45W laptop thermal budget (without a die shrink!) and they did it, but of course performance took a massive hit. Clarksfield was better, but it was scenario dependent and quite often not better by a lot.

Its greatest advantage was indeed Turbo Boost: the Core 2 Quads were worse than Core 2 Duos at the overwhelming majority of tasks most people did. With Clarksfield, you no longer had to make a choice between performance for lightly and heavily threaded workloads. It was also better clock for clock (but, oh, those pitifully low clock speeds...) and had hyper-threading which helps in some scenarios. In retrospect, not a good CPU architecture -- Sandy Bridge manages to be so much better mostly because Clarksfield was pretty bad to begin with.