qcmadness

Core i7-3820: 4c8t, 3.6GHz/3.9GHz, 10MB L3 cache, 130W TDP, $294
Core i7-3930K: 6c12t, 3.2GHz/3.8GHz, 12MB L3 cache, 130W TDP, $583
Core i7-3960X: 6c12t, 3.3GHz/3.9GHz, 15MB L3 cache, 130W TDP, $999

果然無平野:smoke

http://vr-zone.com/articles/inte ... urprises/13298.html

qcmadness

引用:

原帖由 ccw 於 2011-8-16 09:48 發表

$294 very ok la.
It will out-perform 2600k in software like Photoshop CS5 with its quad channel ram.

no

2600k can oc while 3820 cannot

qcmadness

引用:

原帖由 ccw 於 2011-8-16 10:06 發表

Sure if you take OC as an adv of 2600k, while personally I insist to stick with stock freq.
And is it really freq dependent on tasks like Photoshop CS5?

I have heard that a i7 950 can beat 2600 in C ...

yes, freq dependent

http://www.anandtech.com/bench/CPU/25?i=287.288.363.192.100.47

qcmadness

photoshop最重要係freq, 之後先到no. of cores...

qcmadness

引用:

原帖由 ccw 於 2011-8-16 10:43 發表

I see, I did heard someone claiming that the no. of ram channels made a difference for CS5(not 4),
while I cannot remember where I read that.

It was once forwarded by me to this forum.

都唔出奇... 但係相信影響無cpu freq咁大

qcmadness

引用:

原帖由 ccw 於 2011-8-16 10:50 發表

That's what makes me think that SBE 4C8T w/ quad channel rams can be favoring some specific tasks that i7 2600 may show its weakness at.

For it being priced the same as i7 2600, no doubt it is a new ...

so little tasks benefit from extra memory channels...

qcmadness

引用:

原帖由 Henry 於 2011-8-16 15:45 發表

Video editing.
Why CUDA can do much faster than CPU, one of the reason is RAM bandwidth.

of course not...

CUDA / Quicksync do faster because they are not flexible

qcmadness

引用:

原帖由 Henry 於 2011-8-16 17:13 發表

simple maths, but many ops which is not much predictable and few can be cached in L2, so bandwidth to RAM is important. (need big fast pool)
QS not to comment, as mechanism is different.
CUDA, if low ...

cuda / qs做得好既, 都係d predictable既code... 你既concept有少少問題

qcmadness

引用:

原帖由 Henry 於 2011-8-16 23:20 發表

我講既係Data，唔係code.

SIMD data唔駛太大的memory bandwidth

predict到, prefetch到既, 根本唔需要大bandwidth
graphics要咁大bandwidth有時係因為predict唔到

qcmadness

引用:

原帖由 Henry 於 2011-8-17 01:22 發表

The matrices to be processed in film ripping is similar to those in 3D games, often not so predictable. SIMD and AVX do help some due to data batching and perform vector or matrix operations each tim ...

if you know the latency of a SIMD / AVX instruction, you will know why i say that the bandwidth is not important

and do you remember why p4 > c2d has doubled the SSEx performance while the bandwidth remained the same?

qcmadness

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原帖由 Henry 於 2011-8-17 01:26 發表

The robot arms have no use if the transporting band is so slow.

and benchmarks already show that the bandwidth is more than enough and doubling the bandwidth DOES NOT HELP.

qcmadness

and show your data to support your claim that the extra bandwidth will help a lot in some tasks.

qcmadness

http://www.anandtech.com/bench/Product/100?vs=108

i7 950: 3.06GHz / 3.33GHz Turbo / 32.0 GB/s
i7 860: 2.80GHz / 3.46GHz Turbo / 21.3 GB/s

The max of ~10% gain is nowhere significant

qcmadness

引用:

原帖由 Henry 於 2011-8-17 02:59 發表

Increase in bandwidth needs the help of architecture in order to have improvements.
860 and 950 basically is the same chip.

If as you said, bandwidth is not so important, I think CUDA cards in datac ...

if you know tesla has a much lower bandwidth than their desktop counterparts, do you still insist that bandwidth should be as important?

you cannot cut some memory channels in gpus easily because it is tied with ROPs and other parts such as L2 cache that are considered architectural...
you are comparing things that are vastly different

because 860 and 950 are architectually similar, it just proves that adding another memory channel YIELDS LITTLE.

qcmadness

引用:

原帖由 Henry 於 2011-8-17 02:59 發表

Increase in bandwidth needs the help of architecture in order to have improvements.
860 and 950 basically is the same chip.

If as you said, bandwidth is not so important, I think CUDA cards in datac ...

and the large bandwidth is only useful when 2-way and 4-way processors are used

you still don't know why intel and amd wants more memory channels for servers

for desktop, even single channel memory will not scarify much unless IGP / iGPU is used