Official word on hyperthreading..

I know that the official recommendation used to be to turn off hyperthreading.
Is this still the case with more modern processors? Will the system behave better with hyperthreading off? I have a 990x i7 6 core processor.

Not official of course, but I have never bothered to turn off HT and also never had any problems.

Running fine here too with hyper threading still on. Even read here and there that people experienced worse system behaviour with HT off.

My advice:

Try both ways.

If Hyperthreading causes instability, turn it off.
If turning it off causes instability, turn it back on.

If you see better performance with Hyperthreading, leave it on.
If you see better performance with it off, leave it off.

What processors does this affect? I’m going to be using a i7 960 (LGA 1366). Is this affected?
I’m planing, however, to just turn off hyperthreading anyway (dedicated DAW).

What processors does this affect? I’m going to be using a i7 960 (LGA 1366). Is this affected?
I’m planing, however, to just turn off hyperthreading anyway (dedicated DAW).

P.D. sure it isn’t affected.

So what is considered the “first” generation of i7 processors?

So I do have a first generation.

I have an ‘old’ i7 920 which i’ve been running with HT on since day one with no problems! I did try it with HT off for comparison and found i was getting clicks etc…

I run an X79 MB with the 3960k 6c proccy. Enabling HT is no-go here since it results in the Cubase VST Performance monitor to increase by 15% for the same project and also results in more frequent drop-outs under heavy load. I’m rather disappointed since other programs on this machine benefit immensely from HT. But since this is the studio PC, HT remains off.

Yes. Same as me. Pre-Sandy bridge. Good machines, plenty longevity.

been running with hyper threading on for over 2 years with i7 920 and now i7 970 no problems whatsoever.



The issue with hyper-threading technology is more related to low latency recording and monitoring stability. Instability is often caused by a combination of low latencies, cheap motherboards, inferior RAM, buggy 3rd party plug-ins (with lazy high-level coding) and ASIO’s somewhat infancy in load-balancing all of the aforesaid over multiple virtual CPUs (threads).

The use of HT should be taken into account when low-latency recording (and small buffer size) is desired, especially with the older generation CPUs and motherboards. For single-core + HT such as the old Pentium 4, the HT can actually help. The issue came to light when HT on multiple cores (and then dual-socket motherboards) were used for music systems. This was traditionally server technology which had not really been invented for music at all. And the software (drivers) have not yet been fully refined as far as possible to make the best possible use of this hardware technology - BUT we’re getting there slowly.

I’ll explain:
The more virtual CPU threads running in a system, the more synchronization computation is required to load-balance audio processing and I/O tasks between separate threads. That computation takes time. (To over-simplify it the synchronization time can be calculated roughly in the order of t*n where t is the time it takes to synchronize audio processing tasks between 2 threads and n is the total number of threads.) The more threads you have the longer it potentially could take to compute the load-balancing and synchronization. This is both hardware and driver related.

“But doesn’t more threads mean more processing power?”
Yes. It does. But with AUDIO, the processed data needs to arrive at the master bus in the correct order otherwise you’ll be listening to garbage. And if one thread finishes its processing before another, the driver will have to wait anyway for the relevant thread to finish so that it can output the correct data first. This wait, in it’s simplest terms is what we mean by synchronization.

Hyper-threading is fine if you’ve given enough buffer (latency) to allow for the synchronization between the threads. If low-latency is key to your DAW and recording environment then the less threads you have the better. So the key is building a system with good balance between clock speed and number of threads. (On a side note do not over-clock AND use HT if you want stability!)

That said, the NEWER generation CPUs coupled with high-end motherboards do a much better job on the hardware level and you can even get away with a large number of threads (say 12 or more) and a <10ms latency IF you have chosen a great combination of processors, motherboard and audio interface hardware. (PCI-e interfaces being less latent than FW or USB - remember it’s not just thread synch that contributes to latency). So that’s why some of the new Xeon users will tell you they’re not noticing problems. Remember when building an audio system designed for low latency you should read up on the technology of your motherboard, CPU and audio interface. In addition take note of the RAM quality.

( Quick side-note about RAM + HT
Try to avoid using desktop memory for audio systems (which have a crash rate of around once per GB per month) and at all costs stay away from overclocked “value” RAM. Use this RAM with a multi-core hyper-threaded system and you’re set up for embarrassment. That’s one of the reasons why MACs have this “don’t crash” reputation: they use better quality RAM and higher quality motherboards… and yes, you pay that premium. But if you’re building a PC (or Intel based server) lean towards ECC RAM to reduce instability and embarrassing unexplained crashes during sessions. )

Traditionally consumers and PC enthusiasts tend to look at the numbers related to the CPUs ("wow 8 threads in one chip) and neglect somewhat to pay attention to the quality of the motherboard (the thing responsible for hardware synchronization between the 2 CPU sockets for example). You do get what you pay for.

In summary:
Need lots of CPU power for huge projects? Use more threads, allow higher latency
Need “zero-latency” recording? Use less threads and get CPUs with higher clock speed.

Hope that helps guys!

So how does this issue apply to a older MacPro circa 2009?

Hi Robert,

You should conduct your own benchmark testing and understand the bottlenecks of your own hardware. Try comparing recording and playback stability with and without HT switched on.

For example: set up a project with HT off and set the buffer as low as possible in order to record one track well. Then increase the number of tracks you record simultaneously until you reach a maximum before crackles and pops. Repeat this test with your HT switched on and note the difference. You can also make a similar test using various plug-in loads.

The results will be invaluable for your efficiency in sessions and you’ll adopt work-arounds for your bottlenecks.

Perhaps you’d then also like to share your results.


Ok so how does one turn hyper threading on and off in Snow Leopard?

I found that there wasn’t a big power boost with HT on and I did notice better stability with it off on both my I7 920 and now I7 970 systems so I leave it off. I run my RME Digiface at 128 samples with the latest drivers.

Wow, finally someone knowledgeable posting on the forum. Kudos for shining the light through all the mysticism that one hears.

Now I’m going to take this opportunity to beat my favorite horse. Mac performance. I said it. In today’s multithreaded DAW more processing power is spent on thread synchronization than running the plugins themselves! This is why it is CRITICAL for Steinberg to write a native Mac Cubase engine and stop this crossplatform porting of the Windows code that gives us such lame low latency performance. Different kernels require entirely different optimizations for multithreading and this porting from Windows is unacceptable. Steinberg: we need native Cubase for Mac please!

Steinberg: we need native Cubase for Mac please!

Ain’t gonna happen.

Hi there,

Hyperthreading was integrated the first time in the Pentium 4 CPUs and these CPUs made the problems.
A modern I5/I7 with a good mainboard can work without any issue and increase the performance in Cubase 6 or in the HALion 4.
The mainboard is the key in order to get Hyperthreading to work with Cubase. I know from some of our users, that Hyperthreading could be a problem if you use ASUS mainboards on a socket 1155 or 1156. That is why Chris recommended maybe an I5 without Hyperthreading.
Mainboards from Gigabyte on socket 1366 never made any problem with Hyperthreading as far as we know from our users. On my computer in my studio I can gain a real extra performance if I turn Hyperthreading on.

Finally I can not guarantee an extra performance, but on a socket 1366 with activated Hyperthreading it could work.

So I have not any real good news or a guarantee…