Hi LaszloLaszlo Gaspar wrote:Hi all!
My opinion:
Don't buy a hyperthreading CPU for premium price for chess!
My calculations:
When you switch on HT, the OS sceduler balances the thread loads between the virtual processors. You will see 5/8 speed on every virtual processor, because the hyperthread has only 1/4 speed of the real core and it is averaged. You have now doubled cores on 5/8 speed.
5/8 speed means that 8/5 (=1.6) speedup would reach the original, so as every % means around 1 ELO difference, the virtual processors has 60 ELO less . But you have doubled cores, this adds +40ELO. And finally you have a -20ELO on the HT enabled machine which asks for a 20%imply speedup to be on par with the non-HT machine.
So Robert is right until the HT technology is not better and paralel scaling is not better. Worth to mention that Deep Junior scales very well, reaching +70ELO with thread doubling on the CCRL list, and the theoretical maximum is around 100-120ELO.
To go back to the original question the 3770K with less cores is around 20 ELO weaker but it is much-much cheaper, so it is better, but even better is a simple 4 core overclockable CPU without HT as you would not use it for chess and even much cheaper (3570K?).
Basically, we are not contradicting each other. I have marked out in Bold one of your statements.
Let us forget what I said for a moment and simply extrapolate your own statement..... Suppose I'm able to achieve a 30 % speedup on the HT enabled PC ! Then, going by your own logic, I have more than overcome the 20 ELO deficit ! Then, again by your own logic, I have achieved a gain of more than +20 ELO on my HT enabled PC !!!
Let me make things more clear, by extrapolating even the great Robert Houdart's statement...."a 6-core running at 20,000 kN/s will be about as strong as a 12-core running at 24,000 kN/s, or a 16-core running at 26,000 kN/s."
What I say is, Suppose I achieve that 24,000 kN/s speed on just 10 cores NOT 12 ? OR, I achieve 26,000 kN/s speed on 12 cores NOT 16 cores ?
What then ? Did you think of that ?
I should think that in this scenario, I have more than met the conditions stipulated by Mr Robert Houdart, and have indeed achieved an increase in ELO, by a judicious use of Hyper-Threading !! ..... not to mention the changes I have made in the Default Houdini settings and the inherently better HT management in Windows 7 64 bit and Windows 8 .
Your other contention that the 3770 K is better than the 3930K is simply ridiculous. If you don't like HT, it can simply be turned off in the BIOS. The 3930K is highly overclockable, (ridiculously so), that even with HT turned off, it is more than a match for even Dual-Xeons !
Worth every cent I spent on it, I'd say !
