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View Full Version : Which cpu will work well with Lightwave FX8350 or/and i7 4790K ?



yoshiii
01-21-2015, 10:55 AM
Hello

I just bought a FX8350 cpu but I am thinking of returning it for a i7 4790K.

Does the FX8350 perform well with Lightwave? Or is the i7 4790k better?

magiclight
01-21-2015, 03:30 PM
I have an i7-4770 and that beats the FX8350 so I would say the 4790 would do the same, but the FX8350 is much cheaper so you get more CPU for the money,
and it's a good CPU also, but for modeling it does not make much difference, graphics card is king there.

And the renderer has so many cache misses that fast ram and big cache is just as important as a fast cpu.

VonBon
01-21-2015, 03:50 PM
I just built my computer using the 4790k and I'm happy with it.
I did a lot of research concerning the same thing. I can't remember
the terminology used but it was saying something about the 8350
having 8 cores but they are clustered in pairs of 2 and each pair
shared the same 256 bit instruction set or something, and that it
would split the 256 bit whatever essentially making each core limited
to process only a 128 bit instruction set if both cores in the pair were being used.

I tried finding the post but I can't, maybe someone else here may know what I'm
talking about. ;D

magiclight
01-22-2015, 01:31 AM
There are only 4 cores, it behave like it has 8 but each pair share a lot of the logic (floating point units) so sometimes when you run two threads on 1 core they have to wait for each other, but the 4790 does the same thing, but that's ok, you will not notice much difference.

The 4790 is much faster then the 8350 (and almost twice the price ;o), but when you use lots of ram it's not that importanrt, fast RAM access and big cache is much more important, the computer RAM is often 10-20 times slower then the cpu, so with a big cache you win a lot, so as soon as you process some big mesh or texture the cpu will spend a lot of time waiting for ram.

yoshiii
01-22-2015, 04:48 AM
There are only 4 cores, it behave like it has 8 but each pair share a lot of the logic so sometimes when you run two threads on 1 core they have to wait for each other, but the 4790 does the same thing, but that's ok, you will not notice much difference.

The 4790 is much faster then the 8350 (and almost twice the price ;o), but when you use lots of ram it's not that importanrt, fast RAM access and big cache is much more important, the computer RAM is often 10-20 times slower then the cpu, so with a big cache you win a lot, so as soon as you process some big mesh or texture the cpu will spend a lot of time waiting for ram.

So basically it doesn't matter to a point because I am waiting for the ram?
So either processor will be fine?

magiclight
01-22-2015, 05:10 AM
Short answer is yes, it's difficult to say much about performance, the 8350 only have 4 floating point units for all 8 "cores" just as the i7 and I would guess that Lightwave spend a lot of time doing floating point math, so in reality it is closer to 4 threads, the 8350 has a bigger L2 cache while the i7 has a bigger L3 cache, so it's not an easy thing to answer, lets just say that both are very good, I would expect better performance from the i7 but it's also much more expensive.

The i7 use much less power (22nm tech) compared to the 8350, that could be important depending on the power supply in the computer.

Statistics:
The i7 should be around 40% faster for singel thread operations, but it has less cache memory so for large data sets may not be valid.
For multithreading the i7 is just 25% faster but still less cache.

If you use the 8350 make sure you use DDR3-1866 memory, 1333/1600 is slow and don't take advantage of the CPU's higher frequency (the i7 will be happy with 1600).

So once again, I think you will be happy with the 8350, don't exect a huge difference.

yoshiii
01-22-2015, 05:17 AM
Short answer is yes, it's difficult to say much about performance, the 8350 only have 4 floating point units for all 8 "cores" just as the i7 and I would guess that Lightwave spend a lot of time doing floating point math, so in reality it is closer to 4 threads, the 8350 has a bigger L2 cache while the i7 has a bigger L3 cache, so it's not an easy thing to answer, lets just say that both are very good, I would expect better performance from the i7 but it's also much more expensive.

The i7 use much less power compared to the 8350, that could be important depending on the power supply in the computer.

Statistics:
The i7 should be around 40% faster for singel thread operations, but it has less cache memory so for large data sets may not be valid.
For multithreading the i7 is just 25% faster but still less cache.

So once again, I think you will be happy with the 8350, don't exect a huge difference.

OK Thank you.

fazi69
01-22-2015, 09:17 AM
Go with intel. It is much harder to build good system on AMD. You will have to buy expensive motherboard and good cooling to prevent it from throttling. I had fx8350 on three different motherboards and only one ( http://www.asrock.com/mb/AMD/Fatal1ty%20990FX%20Killer/index.pl.asp ) combined with nepton240l was able to render few hours without throttling. Make sure that Your Intel platform have good power section on motherboard as well. DO NOT BUY CHEAP MB! Few years back it was just decision between less or more features on MB but today it is all about POWER SECTION.