Processor i5 vs i7,Hyperthreading

mohdbilal131 · August 26, 2014, 13:01

Hello everyone
I am looking to assemble a desktop with 16GB RAM and I am confused between i5 4690k and i7 4770k processors. Since there is not much of a difference in the clock speeds, I couldn't understand why there is such a huge difference in the prices for the two. Then I found that i7 has 8 threads while i5 has only 4. How much of a different is that going to make if I am using OPENFOAM/FLUENT and working with not more than 5 million cell?

evcelica · August 26, 2014, 16:07

For CFD applications you should be looking at processors with quad channel RAM, the ones you have listed only have dual channel and will be much slower. It's the memory bandwidth that counts for CFD.
Look at Socket 2011 processors like the i7-4820K, or i7-4930K.

Hyper-threading usually does not give much benefit, and can also make computations slower. I always disable hyper-threading on my CPUs.

mohdbilal131 · August 27, 2014, 04:07

Hey evcelica. Thanks a ton for that information. I looked up for 4820K & 4930K , but it seems that they are too costly in my country. I an getting them for something around $650 which at this time I am not willing to shell out. I was concerned about hyper-threading and you seem to have solved the doubt.

evcelica · August 27, 2014, 10:03

The i7-4820K is only $324, which is cheaper than the i7-4770K you were considering, which I find for $334.
I suggest you take another look at the pricing.

petejgm · August 27, 2014, 11:03

X99 boards and Haswell-E launch this Friday. If you're building a desktop computer any time soon they will be the best things you can buy. If money is an issue then the X79 boards and Ivybirdge-E should drop in price after this Friday's launch.

mohdbilal131 · August 27, 2014, 13:58

Quote:

Originally Posted by evcelica

The i7-4820K is only $324, which is cheaper than the i7-4770K you were considering, which I find for $334.
I suggest you take another look at the pricing.

evcelica, the prices on amazon.in are not exactly what you posted, but yeah the difference is not much (only about $40) . So I guess i7-4820K is a better choice. I might also have a look at Haswell-E as "petejgm" recommended.

August 26, 2014, 13:01	Processor i5 vs i7,Hyperthreading	#1
mohdbilal131 New Member bilal Join Date: Aug 2014 Posts: 4 Rep Power: 11	Hello everyone I am looking to assemble a desktop with 16GB RAM and I am confused between i5 4690k and i7 4770k processors. Since there is not much of a difference in the clock speeds, I couldn't understand why there is such a huge difference in the prices for the two. Then I found that i7 has 8 threads while i5 has only 4. How much of a different is that going to make if I am using OPENFOAM/FLUENT and working with not more than 5 million cell?

August 26, 2014, 16:07		#2
evcelica Senior Member Erik Join Date: Feb 2011 Location: Earth (Land portion) Posts: 1,167 Rep Power: 23	For CFD applications you should be looking at processors with quad channel RAM, the ones you have listed only have dual channel and will be much slower. It's the memory bandwidth that counts for CFD. Look at Socket 2011 processors like the i7-4820K, or i7-4930K. Hyper-threading usually does not give much benefit, and can also make computations slower. I always disable hyper-threading on my CPUs. shreyasr likes this.

August 27, 2014, 10:03		#4
evcelica Senior Member Erik Join Date: Feb 2011 Location: Earth (Land portion) Posts: 1,167 Rep Power: 23	The i7-4820K is only $324, which is cheaper than the i7-4770K you were considering, which I find for $334. I suggest you take another look at the pricing. shreyasr and mohdbilal131 like this.

August 27, 2014, 04:07		#3
mohdbilal131 New Member bilal Join Date: Aug 2014 Posts: 4 Rep Power: 11	Hey evcelica. Thanks a ton for that information. I looked up for 4820K & 4930K , but it seems that they are too costly in my country. I an getting them for something around $650 which at this time I am not willing to shell out. I was concerned about hyper-threading and you seem to have solved the doubt.

August 27, 2014, 11:03		#5
petejgm New Member Peter Morgan Join Date: Aug 2014 Posts: 5 Rep Power: 11	X99 boards and Haswell-E launch this Friday. If you're building a desktop computer any time soon they will be the best things you can buy. If money is an issue then the X79 boards and Ivybirdge-E should drop in price after this Friday's launch.