Question Question about using RAM that's faster than my processor

WraithTDK

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Jan 11, 2012
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Greetings. I have an Intel Core i7-9700KF 3.6 GHz 8-Core Processor, and 32GB of Corsair Vengeance LPX DDR4-3600 CL18 Memory on a ROG STRIX Z390-E GAMING mobo. Mistakes were made. I understand that my processor won't support RAM speeds faster than DDR4-3000. I don't think I'm getting the most I can with the default "auto" settings. CPU-Z says it's running as DDR4-2140 and that seems like a damned waste, but at the same time I don't want to make my system unstable, or screw up my processor. Ideally, I'd like to just have the RAM run at DDR4-3000, like the processor is specced for (I'm not overclocking my processor and don't really want to). Should I use Corsair's recommended timing? XMP settings? Leave it as it is?
 

Bob.B

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Greetings. I have an Intel Core i7-9700KF 3.6 GHz 8-Core Processor, and 32GB of Corsair Vengeance LPX DDR4-3600 CL18 Memory on a ROG STRIX Z390-E GAMING mobo. Mistakes were made. I understand that my processor won't support RAM speeds faster than DDR4-3000. I don't think I'm getting the most I can with the default "auto" settings. CPU-Z says it's running as DDR4-2140 and that seems like a damned waste, but at the same time I don't want to make my system unstable, or screw up my processor. Ideally, I'd like to just have the RAM run at DDR4-3000, like the processor is specced for (I'm not overclocking my processor and don't really want to). Should I use Corsair's recommended timing? XMP settings? Leave it as it is?
Put a copy of memtest86 on a flash stick.
Make sure it boots and runs.

Enable xmp.
Boot the flash stick and let it run a pass of the memory.
No errors allowed.

If all good boot windows and test.
 

mamasan2000

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Officially supported isn't saying much. Ryzen 3000 and 5000 officially supports something like 3200 Mhz but very few run at less than 3600 Mhz RAM speed. So you gotta test it.

In terms of memory faster than processor...you are forgetting the latency. This is how it was explained to me.
You are a teacher (The CPU). You are in front of class and have to get your pen (the data).
L1 cache = pen is on your table
L2 cache = pen is on the whiteboard
L3 cache = pen is in your office
RAM = pen is in a neighboring country
HDD = pen is on the Moon
 

Zerk2012

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Greetings. I have an Intel Core i7-9700KF 3.6 GHz 8-Core Processor, and 32GB of Corsair Vengeance LPX DDR4-3600 CL18 Memory on a ROG STRIX Z390-E GAMING mobo. Mistakes were made. I understand that my processor won't support RAM speeds faster than DDR4-3000. I don't think I'm getting the most I can with the default "auto" settings. CPU-Z says it's running as DDR4-2140 and that seems like a damned waste, but at the same time I don't want to make my system unstable, or screw up my processor. Ideally, I'd like to just have the RAM run at DDR4-3000, like the processor is specced for (I'm not overclocking my processor and don't really want to). Should I use Corsair's recommended timing? XMP settings? Leave it as it is?
You should be able to just enable EMP profile in BIOS.
 

WraithTDK

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Officially supported isn't saying much. Ryzen 3000 and 5000 officially supports something like 3200 Mhz but very few run at less than 3600 Mhz RAM speed. So you gotta test it.

In terms of memory faster than processor...you are forgetting the latency. This is how it was explained to me.
You are a teacher (The CPU). You are in front of class and have to get your pen (the data).
L1 cache = pen is on your table
L2 cache = pen is on the whiteboard
L3 cache = pen is in your office
RAM = pen is in a neighboring country
HDD = pen is on the Moon
Right, but my understanding was that even if I forgot latency, Intel didn't when they were creating the specs saying what memory speed their processors supported; and that the purpose of XMP was to get memory to run above JEDEC specs; which is why Intel has a habit of claiming your warranty is void if you run it.

Maybe I'm missing something. I'm trying to understand. I had it boiled down in my brain to "JEDEC SPD=safe and supported, faster ran will simply run slower to match processor spec." And "XMP = performance optimized, but risky if your RAM is already faster than your processor supports." Perhaps I need to revise my understanding?
 

mamasan2000

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Right, but my understanding was that even if I forgot latency, Intel didn't when they were creating the specs saying what memory speed their processors supported; and that the purpose of XMP was to get memory to run above JEDEC specs; which is why Intel has a habit of claiming your warranty is void if you run it.

Maybe I'm missing something. I'm trying to understand. I had it boiled down in my brain to "JEDEC SPD=safe and supported, faster ran will simply run slower to match processor spec." And "XMP = performance optimized, but risky if your RAM is already faster than your processor supports." Perhaps I need to revise my understanding?
https://www.intel.com/content/www/us/en/gaming/extreme-memory-profile-xmp.html
eXtreme Memory Profile. Yes, it's going beyond JEDEC spec. JEDEC is slow and loose timings. I view it as Server-spec. They don't overclock, in the enterprise. 99.9% uptime is more important than 5-10% more performance.
Maybe an analogy will help, Think of RAM as temporary storage. Like a faster SSD/HDD. Do you freak out if your HDD spins at 7200 RPM? That is higher than 3600 Megahertz.
Ram bandwidth is about 50-70 gigs/sec. On Ryzen 5000, L3 Cache has around 600 gigs/s bandwidth, L2 is around twice that and L1 is again around twice as high. So to the CPU, your RAM looks like a superslow HDD.
 
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WraithTDK

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https://www.intel.com/content/www/us/en/gaming/extreme-memory-profile-xmp.html
eXtreme Memory Profile. Yes, it's going beyond JEDEC spec. JEDEC is slow and loose timings. I view it as Server-spec. They don't overclock, in the enterprise. 99.9% uptime is more important than 5-10% more performance.
Maybe an analogy will help, Think of RAM as temporary storage. Like a faster SSD/HDD. Do you freak out if your HDD spins at 7200 RPM? That is higher than 3600 Megahertz.
Ram bandwidth is about 50-70 gigs/sec. On Ryzen 5000, L3 Cache has around 600 gigs/s bandwidth, L2 is around twice that and L1 is again around twice as high. So to the CPU, your RAM looks like a superslow HDD.
Sure, I understand RAM's function and all, I just kind of have mental block on timing. Intel says using XMP can void the processor warranty because you're forcing the processor to work outside spec to communicate at the proper speed, effectively overclocking the processor. That concerns mec particularly because while I like Intel processors, it's no secret that Ryzen's are for more geared towards overclocking than anything team blue is putting out
 

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