Maximum Addressable Memory for Haswell Extreme Chips

A

aphexcoil

Limp Gawd
Joined
Jan 4, 2011
Messages
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64GB or 128GB? I've seen both. Can we get confirmation from someone in the know if the three new Haswell-E (X99 Platform) chips can address 16gb SIMMS when they are finally available?
 
Officially? 64gb. Unofficially? Probably 8 of the largest DDR4 consumer sticks whenever they come out. They cannot validate for products that don't exist yet.

It was the same thing with LGA 1366. The largest DDR3 sticks at the time were 4gb, so it was validated at 24gb max memory support. Yet they had no issues running 48gb with 6x8gb sticks.
 
EVGA says 128gb so I doubt they'd be lying about that. ARK might say 64 because that's all that can be had right now so that's all they can claim is "validated".
 
I saw this post once, but I'm not sure how valid it is:

Byte number 4 of the SPD defines the devices density and banks used on the memory modules. If Byte 4 is set to 4, it means the memory module uses 4Gbit chips. If Byte 4 is set to 5, it is a 8Gbit chip.
The MRC code in the BIOS of Intel CPUs contains a command called "ASSERT" which limits the maximum value of Byte 4 to 4.
If Byte 4 = 5 (for 8Gbit), the MRC will stop -> the system does not boot!
And this is exactly what is happening here on the majority of Intel CPUs.

That being the case, I'd like to research if the Haswell-E's have been restricted in some way.
 
I saw this post once, but I'm not sure how valid it is:

Byte number 4 of the SPD defines the devices density and banks used on the memory modules. If Byte 4 is set to 4, it means the memory module uses 4Gbit chips. If Byte 4 is set to 5, it is a 8Gbit chip.
The MRC code in the BIOS of Intel CPUs contains a command called "ASSERT" which limits the maximum value of Byte 4 to 4.
If Byte 4 = 5 (for 8Gbit), the MRC will stop -> the system does not boot!
And this is exactly what is happening here on the majority of Intel CPUs.

That being the case, I'd like to research if the Haswell-E's have been restricted in some way.
Click to expand...

AIUI with X79 the standard memory initalisation code was limited to 4 gigabit chips (8 gigabyte dual rank modules) but at least one vendor released special bioses to support 8 gigabit chips (16 gigabyte dual rank modules).

http://rog.asus.com/340082014/rampa...e-iv-black-edition-and-asus-x79-motherboards/

I would be very surprised if haswell E did not support 16GB modules at some point but when desktop 16GB DDR4 modules will become available at a reasonable price is anyones guess.

Note that at least with DDR3 server modules used special "registered" chips which allowed quad rank modules and hence double the module size for a given chip size that desktop modules have.

If you can reasonablly forsee a need for more than 64GB of ram I would be seriously considering a dual socket workstation/server platform. They have more slots than desktop platforms AND can support the quad rank registered ECC modules.
 
Tsumi said:
Officially? 64gb. Unofficially? Probably 8 of the largest DDR4 consumer sticks whenever they come out. They cannot validate for products that don't exist yet.
Click to expand...

So you're saying as soon as 16GB modules are available they can be plopped in and will work, without anything like a BIOS update ?
 
MasonDesigno said:
So you're saying as soon as 16GB modules are available they can be plopped in and will work, without anything like a BIOS update ?
Click to expand...

Maybe it'll require a bios update, maybe it won't. I'm just saying, if it's anything like the i7 920, it will work fine. The i7 920 was officially validated at 24gb, and had no problems running 48gb.
 
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