Dual Cores with HT or Quad-Core with single Thread

[bljoseph]

I am trying to make a mobile processor decision. I am interested especially in the Sandy Bridge architecture. I need some speculatory (I submitted it to Webster's) advice. I am forward looking in my choice of hardware and I want the best bang for the buck.

I am largely a productivity software person with some occasional image recognition scanning included. I don't do photoshop but I will on occasionally get drawn into some gaming. I can see myself getting into video editing now that I "Droid". Given this info I am looking at these possibilities:


i7
i5 dual
i5 quad

Excuse my ignorance but I believe that there are supposed to be two options in the i5 that will essentially handle the same amount of threads but with a different core count (Two vs 4). Given the way that software is written and might be written what do you think will be the way to go. Often the dual will have a higher hertz. I know very few big software companies (exception of Adobe) write to utilize threads well. I don't know if this question should be in the applications section or not. My thinking is if I have "poorly written" software then I would want a dual core with higher speeds and HT. I think the OS might run on a dedicated and apps on the other. I don't know but I want bang for my buck and it doesn't make sense paying a premium now and waiting 8 mos for software to utilize my hardware. Thoughts?

 

[jprahman]

A quad-core without hyper-threading will destroy a dual-core with hyper-threading. Basically what hyper-threading does is it runs two threads on the same CPU core, duplicating only necessary resources like CPU registers. Because the execution resources of the CPU core are being shared by two threads it means that each thread is making only 50%-60% as much progress as it would if it were running on it own core. As a result you only get a 0%-20% boost over a dual core without hyper-threading, a quad-core otoh would give you twice the performance as a dual-core because you have twice the actual execution resources, rather than just sharing the same resources.

So I would recommend a quad-core because even though not all software uses more than a few cores if you have multiple programs running at the same time each program can run on separate cores, rather than having to be interleaved between cores. Besides, quad-cores are more future proof. It is true that quad-cores often run a slightly lower clock speeds, but if you go with an newer Intel quad-core you'll get the benefit of turbo-boost, which ramps up clock speed when some cores are idle. What's really nice about turbo boost is that the fewer cores that are active the higher clock speed are achieved, so singled threaded code can run at high speeds. All of this frequency tuning is done automatically by the CPU in realtime in response to signals from the OS and thermal sensors on the CPU itself.

Edit: Image recognition software and video editing software would see a pretty significant improvement running on a quad-core compared to a dual-core, hyper-threading or no hyper-threading.