8400 turbo on all cores?

P4Clock · 17 Oct 2017 at 09:05

my 1150 system died two weeks ago and i am in the middle of building a new one, it was going to be based of the AMD 1600.

how ever i am now very interested in the 8400 at the price point, with older none k CPU's you could set all cores to run max turbo at all times. is this still the case? and can the 8400 maintain max turbo over all 6 cores?

pastymuncher · 17 Oct 2017 at 09:27

I suppose it's going to come down to the choice of motherboard and cooling although it would seem that 3.8Ghz on all cores is the norm.

imginy · 17 Oct 2017 at 10:12

There are many reviews out there that show the 8400 runs at 4ghz when 1 core is being used 3.9ghz when 2-4 cores are being used and 3.8ghz when all cores are loaded.

Just to add it can do this fine on stock cooler.

P4Clock · 17 Oct 2017 at 11:15

For the cost That's a fantastic chip

jabski · 17 Oct 2017 at 18:34

8400 wont do 4ghz across all 6 cores with MCE on

P4Clock · 17 Oct 2017 at 19:48

jabski said:
8400 wont do 4ghz across all 6 cores with MCE on

And with it off?

P4Clock · 17 Oct 2017 at 19:51

With older cpu's you could turn off turbo and go into core setting telling it to sync all cores and them set them all to max turbo ratio

southernorth · 17 Oct 2017 at 20:49

P4Clock said:
And with it off?

With MCE on it does 3.8ghz all cores, but runs hotter due to higher voltage. With MCE off it still runs at 3.8ghz all cores, but with less heat and voltage.

EVH5150 · 17 Oct 2017 at 20:59

GWANGY · 21 Oct 2017 at 11:33

DIdnt linus tech tips do a vid on this very thing and posited that the low stock speed (2.8) was na indicator that the chip would struggle to reach the rated speeds (3.8ghz) when all cores were in use. Borne out by the fact that intel no longer quotes all core turbo speeds... Shame as this looked to be the goto chip from my 2500k...ymmv howvever..

jigger · 21 Oct 2017 at 11:57

GWANGY said:
DIdnt linus tech tips do a vid on this very thing and posited that the low stock speed (2.8) was na indicator that the chip would struggle to reach the rated speeds (3.8ghz) when all cores were in use. Borne out by the fact that intel no longer quotes all core turbo speeds... Shame as this looked to be the goto chip from my 2500k...ymmv howvever..

It might still be in time. Once the mobile, Xeon and higher binned Coffee lake chips have filled the market quality parts might be filter down to the 8400.

I think the trick to the 8400 will be finding the right batch in 6-12 months.

GWANGY · 21 Oct 2017 at 12:00

I think the trick to the 8400 will be finding the right batch in 6-12 months.

read my mind .. also to read further reviews...

CAT-THE-FIFTH · 21 Oct 2017 at 12:21

Once better quality chips are out they will be released as the Core i5 8500 and Core i5 8600 non-K. I expect those will be probably be released when Ryzen+ is out.

southernorth · 21 Oct 2017 at 16:51

CAT-THE-FIFTH said:
Once better quality chips are out they will be released as the Core i5 8500 and Core i5 8600 non-K. I expect those will be probably be released when Ryzen+ is out.

What do you speculate that the i5 8500 and i5 8600 will boost to on all cores?

CAT-THE-FIFTH · 21 Oct 2017 at 17:45

southernorth said:
What do you speculate that the i5 8500 and i5 8600 will boost to on all cores?

Well looking at the 7000 series,I would expect a Core i5 8500 to have a higher base clockspeed and probably another 200MHZ on the boost clock,ie,so maybe something like 3.0GHZ/3.2GHZ~4.0GHZ,and the Core i5 8600 would probably be a slightly downclocked Core i5 8600K,so maybe something like 3.2GHZ/3.4GHZ~4.2GHZ,at least if we look at the previous generation SKUs and the difference between the CFL Core i7 SKUs.

Journey · 21 Oct 2017 at 17:56

I'm unsure why people are of the idea that the 8400's will not turbo boost to 3.8GHz on all cores for every chip that is labelled as one by Intel. The current 14nm process is very mature now, and the K chips are hitting 5.0GHz easily, the and the previous generation 7400/7500/7600 had no issues running at their respective boost speeds.

People question the reason why they stopped publishing all-core boost clocks, like it was some sort of conspiracy that there must be issues with the silicon, I'd be more inclined to say that they are trying to keep the 65w advertised TDP on these 6 cores chips, and also don't want to advertise just how fast they actually can be, reverse marketing in effect so chips that are better are still chosen as an option. People look at the base clock of 2.8GHz and think, well that's pants, but if they know it's going to happily run at 3.8GHz all day long, why spend the extra $50 on the i5 8600 which has a 3.4GHz base clock, and 4.0GHz all core turbo? (i5 8600 numbers are just estimates)

I'd buy, and eat a hat, if anyone's i5 8400 doesn't hit the 3.8GHz all core turbo, after all it boosts up to 4.0GHz on a single core, so all the cores need to do at least that speed, at one time or another.

gavinh87 · 21 Oct 2017 at 18:00

Journey said:
I'm unsure why people are of the idea that the 8400's will not turbo boost to 3.8GHz on all cores for every chip that is labelled as one by Intel. The current 14nm process is very mature now, and the K chips are hitting 5.0GHz easily, the and the previous generation 7400/7500/7600 had no issues running at their respective boost speeds.

People question the reason why they stopped publishing all-core boost clocks, like it was some sort of conspiracy that there must be issues with the silicon, I'd be more inclined to say that they are trying to keep the 65w advertised TDP on these 6 cores chips, and also don't want to advertise just how fast they actually can be, reverse marketing in effect so chips that are better are still chosen as an option. People look at the base clock of 2.8GHz and think, well that's pants, but if they know it's going to happily run at 3.8GHz all day long, why spend the extra $50 on the i5 8600 which has a 3.4GHz base clock, and 4.0GHz all core turbo? (i5 8600 numbers are just estimates)

I'd buy, and eat a hat, if anyone's i5 8400 doesn't hit the 3.8GHz all core turbo, after all it boosts up to 4.0GHz on a single core, so all the cores need to do at least that speed, at one time or another.

100% this. Its the tin foil hat guys out there again.

CAT-THE-FIFTH · 21 Oct 2017 at 19:10

Yeah,Intel sets its base clockspeeds low so it can hit the rated TDPs,under certain conditions. So if you have enough cooling and power it should in theory never be at base frequency anyway.

Jono8 · 21 Oct 2017 at 20:00

Going to be building an i5-8400 build next friday for my nephew so i will let you know! Managed to pick up one of the few left in stock for £170 which was fortunate. A lot of retailers bumping the price up it seems if stock is available.

TallPaul1878 · 21 Oct 2017 at 21:08

Well going by the reviews and other people's testimonies I'd say the i5 8400 is the golden chip right now.

Looking at benchmarks it doesn't seem to warrant the extra cash to go with a K series CPU. For example, the price of the i5 8600k with a decent air cooler and a GTX 1070 is going to be too similar to the price of an i5 8400 and a GTX 1080, even if you do decide to replace the stock cooler with a modest aftermarket air cooler.