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Quick IF / Memory Question

m4cc45

m4cc45

m4cc45

Soldato
Joined
10 Mar 2003
Posts
6,790
Hi

Currently have a 3700x and Aorus Pro MB with Viper 4000 memory.

using XMP seems fine but noticed there is a coupled mode. Is this better to use? Using it at 2000 causes the system not to post. Is it worth dropping the memory down to 1800?

Sorry not sure on the right forum area for this.

Thanks


M.
 
Manual is the way to be honest, the built in profiles change quite a lot and you really want to dial in and test best possible frequency and then timings. If you push over 3600 be mindful you should be increasing the FCLK or you introduce a load of latency...

Memtest it as it can be error central, I would personally aim more at a rock solid 3600 and good timings.
 
Smffy said:
Manual is the way to be honest, the built in profiles change quite a lot and you really want to dial in and test best possible frequency and then timings. If you push over 3600 be mindful you should be increasing the FCLK or you introduce a load of latency...

Memtest it as it can be error central, I would personally aim more at a rock solid 3600 and good timings.
Click to expand...

This, the IF Clock goes from a 1:1 to a 1:2 ratio above 3600.
 
Hi

Thanks for the replies - just trying to gauge which is better?

Memory seems stable using XMP (4000-19-19-19-39) which is what it was purchased at (so no overclocking as such) would reducing it to 3600 be better?

Thanks,


M.
 
m4cc45 said:
Hi

Thanks for the replies - just trying to gauge which is better?

Memory seems stable using XMP (4000-19-19-19-39) which is what it was purchased at (so no overclocking as such) would reducing it to 3600 be better?

Thanks,


M.
Click to expand...

With tighter timings, yes.
 
Go for 1:2 (not 1:1 my bad) and lower the timings on the ram, instead of upping the speed, 3800 ram and lower timings etc
 
Last edited:
I already answered this question pretty comprehensively in your other thread. :rolleyes:

Link.

1900MHz FCLK is pretty golden. Your be between 1800MHz and 1900MHz FCLK.

Then ram FCLK x 2.

Then tighten timings.
 
m4cc45 said:
Hi

Thanks for the replies - just trying to gauge which is better?

Memory seems stable using XMP (4000-19-19-19-39) which is what it was purchased at (so no overclocking as such) would reducing it to 3600 be better?

Thanks,


M.
Click to expand...

I would just check it is actually running at that because 4,000 is pretty high mem clock on that chip. What does it look like in CPUZ? I would run memtest to see if it’s stable as again not exactly many getting that memory speed without massive effort.
 
Smffy said:
I would just check it is actually running at that because 4,000 is pretty high mem clock on that chip. What does it look like in CPUZ? I would run memtest to see if it’s stable as again not exactly many getting that memory speed without massive effort.
Click to expand...

I'll post a picture later, currently running, stable, at:

From CPUz:

1996.0Mhz
3:60
20.0 Clocks
19 Clocks
19 Clocks
39 Clocks
68 Clocks
1T

@opethdisciple sorry thought it was a different question - if that's not the case, which it sounds like it isn't, I'll take that info onboard :)

Thanks.



M.
 
As no one has actually told you the 'why' yet here goes.

The reason why you want a 1:2 (coupled) frequency between your FLCK and ram frequency is because when you run it 'uncoupled' (which your free to do) it introduces an extra 10ns of latency for memory access, which in generally isn't worth it.

So in general if you are running an FCLK of 1900MHz with ram at 3800MHz your pretty much golden as this is generally considered the upper range for the 3700x/3800x/3900x CPU's.

As far as I know the Ryzen 3600 series cant run as fast as this.

---

To put it in to perspective my 3700x can only do 1800MHz FCLK so I set my ram to 3600MHz. That way it is coupled and I do not get this +10ns memory latency penalty.
 
Depends on the board I think. Mine when left on auto will not raise FCLK above 1800 MHz, whereas AMD says IF should be capable of running at 1866 MHz and some can get theirs to 1900 MHz. RAM + IF at 1866 MHz (3733 MT/s) or 1900 MHz (3800 MT/s) will definitely perform better than having the RAM at 4000 MT/s.
 
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