by Rob Williams on August 29, 2014 in Processors
In late 2011, I wagered that Intel would follow-up its i7-3960X with an eight-core model within the year. That didn’t happen. Instead, we have had to wait nearly three years since that release to finally see an eight-core Intel desktop chip become a reality. Now for the big question: Was the company’s Core i7-5960X worth the wait?
The faster the processor, the better its bandwidth and latencies are. Where memory is concerned, however, there are many more factors at play. While frequency plays a major role in overall memory performance, the memory controller can make an even greater improvement, based on its implementation and also its capabilities.
With Intel’s X79 and X99 platforms, we’re given a quad-channel controller, while Intel’s (and AMD’s) other platforms stick to a dual-channel design. A quad-channel controller could in theory provide twice as much bandwidth as a dual-channel one. How the controller is integrated into its chip along with the memory’s frequency determines the latency.
While faster memory bandwidth and lower latencies can improve overall computer performance, the faster each core can work with one another along with how much bandwidth a cache can handle rounds out the most important factors of PC performance. The results of all of these are tackled on this page.
- Core i7-5960X: Corsair Vengeance LPX 4x4GB DDR3-2666 16-16-16
- Core i7-4960X: Kingston HyperX Beast (4x8GB) – DDR3-2133 11-12-11
At this point, DDR4 isn’t blowing our socks off. In fact, given the premium that must be paid on DDR4 modules, these gains are downright underwhelming. Of course, I should note that 2666MHz is not the “max” speed that DDR4 can manage. In fact, the modules I’m using support up to 3000MHz (despite being advertised for 2800MHz). But that said, some memory frequencies will require the CPU to overclock; 2666MHz is one of those frequencies that doesn’t.
I mentioned on the first page of this article that at the moment, scaling above 2666MHz on Haswell-E is a little sketchy at this point in time, and it’s not clear to me why. When I benchmarked our memory kit at 2800MHz, Sandra spit out a result of 49.5GB/s bandwidth – roughly 3GB/s less than when the kit was clocked at 2666MHz. That’s pretty nonsensical.
Here’s the reality: People who buy DDR4 for their Haswell system are going to be paying for roughly the same performance that they could get from DDR3, or perhaps even worse. Buying a very fast kit of DDR4 and seeing lower performance than 2133MHz DDR3 sticks is bizarre, so hopefully it won’t take long for board vendors or whoever needs to fix things, to fix things. Once this launch settles, I plan to take a deeper look at this subject. For now, let’s see how other memory-related performance fares.
Interestingly, L3 speed decreased slightly, while L1 speed increased dramatically – it’s more than 2x!
Latencies on the X99 platform fared worse than those on the X79 one. On the DDR4 side, that was definitely to be expected, given the looser timings (which are a side-effect to the lower voltages). Bandwidth-wise, the eight-core chip reigns supreme, but even in that test, the inter-core latency is higher as well.