by Rob Williams on November 3, 2008 in Intel Processors
With Core i7′s launch due in just a few weeks, there’s no better time than right now to take a hard look at its performance, which is what we’re taking care of today. In addition to our usual performance comparisons with last-gen CPUs, we’re also taking an in-depth look at both QPI and HyperThreading performance, and some of our results may surprise you.
When picturing a “hardcore” application in your mind, Office probably isn’t the first one to come to mind. However, as it seems on the surface, Microsoft takes multi-threading very seriously, and I think many other software developers can be taught a lesson. Math in general seems simple, but as you can see in the graph below, the application was able to take advantage of all eight threads, which is to me, quite impressive.
The differences aren’t mind-blowing, but an 18% increase in performance simply by enabling HyperThreading is rather substantial. It’s not so important with Excel, but it gives us a general idea of just how much more efficient other software applications could be, if they were truly multi-threaded.
Sandra has been a favorite of ours for quite a while, for more than one reason. One of the better reasons is because it allows us to test out a variety of tests from within one application, which is nice, especially when you want to quickly test various sub-systems on the PC. Below, we offer five different graphs from Sandra, tackling memory, math and multi-core performance.
The results are quite interesting so far. In our Arithmetic test, HyperThreading made almost no difference where the Whetstone floating-point benchmark was concerned, but it made an incredible difference with the Dhrystone result… 59%!
Similar enhancements are seen with our Multi-Media tests, with each one of the tests being substantially enhanced with HyperThreading enabled.
Earlier in the article, I pointed out that HyperThreading changes just how efficient the Cryptography test is, and here’s proof. Oddly enough, AES256 thrives on HT, but SHA256 absolutely doesn’t. Disable HT entirely, and the results swap places, with SHA outperforming AES. Luckily, the differences in the grand scheme of things are minor, but it’s interesting nonetheless.
If there is one area where neither the QPI speed (at least, within our current limits) nor HyperThreading affected the memory bandwidth and latencies whatsoever. Although I’ve only included the results from the bandwidth above, you can be rest-assured that the latencies were absolutely identical as well.
Finally, our most interesting graph might be the one seen above. With HyperThreading enabled, the inter-core performance is truly incredible… far exceeding the performance of Core 2. With it off though, things change, with the latency and bandwidth actually performing slightly worse than what we saw with the QX9770.
So as it seems, when it comes to inter-core performance, Core 2 Quad is actually a little more efficient, which could be due to a few factors, one being tighter integration of components, and less components in general. But this is one thing that QPI should increase, you’d imagine, but as seen above, adjusting from a 4.8GT/s to 6.4GT/s QPI makes virtually no difference. Luckily, these lack of efficiency doesn’t mean much, since HyperThreading is designed to be turned on all the time, as it really should be.