Does hyperthreading on client PCs have any impact on network performance?

Question

My knowledge of networking is pretty minimal, and my hardware knowledge is only slightly better so please bear with me. I work for a small non-profit that's getting a new computer network set up by another company. The server that they'll be installing is an HP Proliant ML350p G8, Intel Xeon E5-2620 v2 2.1GHz, 8GB RAM running Windows Server 2012 R2.

We use our computers for MS Office programs (Word, Excel, and Access) and web browsing. The most intensive task we do is searching the Access database. From my understanding, hyperthreading, and the extra expense that comes with it, would not be beneficial with our usage, but the company doing our new network is recommending hyperthreaded processors on the client computers.

So my question is, would having a hyperthreaded processor on the client computers impact network performance?

Specifically we're looking at an i3-4150 3.5GHz vs AMD A6-5400K 3.6GHz processor, and about a $70-80 difference per machine. I just don't want to get suckered into paying more money than necessary, since these are donor dollars and we don't want to spend any more than necessary on administrative costs.

Answer 1

This seems like an opinion question, but the general answer (citation needed) is that networking is a few orders of magnitude slower than CPU and memory, for a reasonably modern computer. So no, speeding up the CPU some won't measurably affect network performance.

Application performance is another story, of course. The only way to know for sure is to measure the performance under the different options.

Answer 2

CPU speed might have affected network performance 15-20 years ago. Back then most computers only had one processor... so if the CPU was being heavily utilized the network card and operating system may of had to wait for other execution to complete.

Modern desktop computers have anywhere from 2 - 8 processors. It is rare for a typical computer user to utilize 100% of all of the processing power. Most modern network cards have TCP offloading such that the network card internally process some of the functions needed to handle the TCP/IP stack.

There is always plenty of available processing power to handle networking and operating system functions...so network performance isn't even a consideration in your decision making process.

Hyperthreading is a technology that turns a physical processor into two logical processors. With processors that have 4+ cores the benefits are likely minimal (again, the average user won't use all of the processing power).

I would recommend you go with the Intel CPU's. Intel processors handle more instructions per clock cycle and are thus faster for single threaded applications. Because not all software can parallelize easily and multithreaded programming is difficult, there is a lot of software out there that is still single threaded(and thus will get minimal benefit from multiprocessing). You can expect the Intel CPU to be around 10-15% faster, which is well worth the extra $70.

Intel is also a safer option politically as they are the de facto standard. If you have a problem down the road it may be questioned why you decided to cut corners to buy AMD hardware (fairly or not).

Answer 3

Hyper-threading is about improving local system performance, and has little to do with network throughput. Of course, a well-functioning CPU may be able to push more bits into your network, but that's not usually the limiting factor. That said, hyperthreading can produce a real CPU performance benefit on your systems; I've read that this performance increase runs between 15 and 45 percent, depending on the workload and who you listen to.

Here's where it gets tricky. Even on your local system, most of the time you don't notice this performance benefit. This is for two reasons. The first is that the benefit comes in the form of virtual additional processors, and many local tasks just aren't well-suited to running over multiple CPUs. Even those tasks that are suited for this need to be coded correctly to take advantage of it. The second reason is that the dirty secret of desktop performance today is that it's not about the CPU any more; it's about the hard disk. So even if you have a system that would take advantage of hyperthreading nearer the 45% mark than the 15% mark, you'll still probably get a lot more bang for your buck ensuring that you have good hard disks and enough RAM. Where I believe hyperthreading really shines is in those situation where you sometimes have a process with several threads that runs away with your CPU. Hyperthreading can help ensure you always have available CPU time for normal desktop tasks.

Now let's talk about your specific scenario. Even after everything I've said about hyperthreading, I'd still strongly recommend the Core i3 processor. This is for two reasons. The first is that I think you'll find there are several intangibles involved, such that you'll be vastly happier with the Intel-based system. There was a time I would have gone the other way on this, but in recent years I've had much better results going this route. A big part of this is that what makes for reasonable performance today won't hold up a few years down the road. You need to buy PCs today that will have acceptable performance throughout their service life. This leads to the second item: Excel and web browsing aren't exactly "simple" any more in terms of performance, and this trend is getting worse, rather than better. Excel can be made to work as a full-fledged data processing system, and web sites are pushing more and more work via javascript onto end-users computers. Either of these can easily put a lot of work on your CPU, and probably are (or will), if that's how you're running your business.

The upshot is that there's a lot of benefit to be had for relatively small cost, especially compared to the cost of your employee's time, from providing well-specced computers. For this specific model, you only need to save less than a minute per day of your employee time over the life of those CPUs to get savings that exceed their cost difference, even at minimum wage¹.

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_{¹Cost difference of $80 spread over and estimated 4 years and ~220 work-days per year is about 9.1¢ per day. At $7.25/hr it takes about 45 seconds to earn 9¢}