Intel Pentium G4400: Benchmarking A ~$60 Skylake Processor

[Guest]

... all Core chips have AVX/AVX2, it's just that Intel decided to fuse them off to create different segments. (AVX-512 is a different story.)

Skylake G4400 has 256-bit AVX2 units and an AVX2 instruction decoder, but they are disabled? Can you please point me to a reliable source stating this?

[artivision]

Skylake G4400 has 256-bit AVX2 units and an AVX2 instruction decoder, but they are disabled? Can you please point me to a reliable source stating this?

Its exactly as the guy above said and your opinion is painfully wrong. The truth is "ALWAYS" as the guy above said, they simply cut something that is supposed to be for the privileged and purposely degrade the product. Skylake Pentium has 256-bit registers with AVX2 deactivated, but the second 128-bit are not deactivated, they are used for other purposes.

[ldesnogu]

Skylake G4400 has 256-bit AVX2 units and an AVX2 instruction decoder, but they are disabled? Can you please point me to a reliable source stating this?

It'd be hard to prove unless die-shots are shown. But do you think Intel wants to multiply masks, implementation efforts, and validation efforts, especially for lower-cost chips? I don't

As I wrote AVX-512 is different. Its area and impact on other part of the design is likely much larger than AVX2 to have it just sitting there disabled.

[Guest]

Its exactly as the guy above said and your opinion is painfully wrong. The truth is "ALWAYS" as the guy above said, they simply cut something that is supposed to be for the privileged and purposely degrade the product.

A question isn't an opinion. It's just a question.

Skylake Pentium has 256-bit registers with AVX2 deactivated, but the second 128-bit are not deactivated, they are used for other purposes.

For what purposes are those higher 128 bits of the 256-bit YMM registers used?

Are you also claiming that 1 MB of L3 cache and hyperthreading are also disabled on Skylake Pentiums? Compared to Skylake i3.

[norsetto]

How many Cray-2 could we make with one of these?

[artivision]

A question isn't an opinion. It's just a question.



For what purposes are those higher 128 bits of the 256-bit YMM registers used?

Are you also claiming that 1 MB of L3 cache and hyperthreading are also disabled on Skylake Pentiums? Compared to Skylake i3.

Ok, Intel said that their Pentiums are based on the strong models "Haswell Pentium", if they had different units that would be fraud (different tech), so they have the same units. Then, from a 256-bit register you cannot cut the half, it isn't possible to cut half the unit (to any unit). That you can cut is an entire 256-bit unit or an entire ADD unit so you have only 256-bit MADD. Now on Skylake if they are two different techs 256-bit and 512-bit, then the desktop (i3 and Pentium) has the first and the server has the second. If they are only one tech this means that they all have 512-bit registers but i3 runs only the 256-bit AVX from the set. That doesn't mean that the rest of the unit is not usable or that you can cut it. Thats why "probably" the Skylake Pentium that is equal to Sandybridge i3 2120 massacres the i3 almost +50% on CRay.

The reason that i talk you back isn't a technical mistake that you made, but because you believe that there is a possible world where Intel wouldn't do that.

[bug77]

Why does the article say that the " i5 6600K goes for around $299~320"? I got mine a couple of weeks ago from Microcenter for $229.99.

[ldesnogu]

Are you also claiming that 1 MB of L3 cache

L3 is a different beast as other parts of the chip so it's easier to validate it separately. But L3 is small compared to core size so it'd probably be less expensive to just fuse it off.

Look at this discussion on RWT which includes die shots with LLC labeled to see how small L3 is.

and hyperthreading are also disabled on Skylake Pentiums? Compared to Skylake i3.

Most likely yes. Hyperthreading is very intrusive in a design, and Intel wouldn't be crazy enough to design different cores just to remove HT.

[kaprikawn]

Hmmm, I may look into this, thanks for bringing it to my attention. My current Linux system has a first gen i5 750 (which was basically my old Windows gaming machine). It is very loud. I haven't bothered to work out what is actually loud but I think it's my CPU fan. I've purchased a new CPU fan but haven't fitted it yet, if that doesn't do the trick I'll want to upgrade to a more recent processor with a lower power draw (hell, I might want to do that anyway, the i5 is getting on a bit now).

I've just run the test and I'm getting :
John the Ripper :
Mine 1885 vs 2017 G4400
7-zip
Mine 7667 vs 7465 G4400
C-Ray
Mine 55 secs vs 46 secs

So they're comparable, the G4400 wins in 2 out of the 3 tests. My question is would this relate to similar gaming performance, would this be a viable CPU for gaming on Linux? The concern is dropping from 4 cores to 2, but I don't think that'll make much of a difference, not for now anyway. If it becomes an issue in a year or so I can upgrade again then. With a new mobo I would just be able to get the CPU which wouldn't be that big of a deal. Having to change both the CPU and the mobo at the minute would necessitate keeping costs low, this CPU could be a good stop gap.

[carewolf]

A question isn't an opinion. It's just a question.



For what purposes are those higher 128 bits of the 256-bit YMM registers used?

Are you also claiming that 1 MB of L3 cache and hyperthreading are also disabled on Skylake Pentiums? Compared to Skylake i3.

Not the cache, but everything else. And it is not speculation, it is how Intel has been operating for over a decade. The cheapest Intel CPUs are often identical to more expensive versions, except more effort has been put into producing the cheap ones compared to the expensive ones because they are the expensive version + extra work to deliberately cripple them.

On the other hand that makes it possible to sell processors cheap to consumers while still maximizing earning those that need more than basic features.