How would I determine what is the maximum memory that Athlon II X3 450 will support on a Asrock 970 Extreme3 series motherboard?

BIOS shows 32GB (4x8GB), tried with both 1333 and 1066 speeds.

Windows Ultimate x64 shows 32GB installed, 24GB available.

Debian based x64 OSes(Ubuntu etc) just show 24GB, BUT lshw -C memory and dmidecode -t 17 show that all 4 8GB chips are found.

Motherboard states that 32GB is supported, thus my strong suspicion is that the limit has to do with the CPU, as I reused Athlon II X3 450 from an older build (880 M/B) waiting to pick up FX-8320 or 8350 later.

I also "unlocked" the CPU to Phenom x4 but that did not help the matters.

What CPUs would support 32GB on 970 motherboard?

 

CPU-Z excerpts:

Name AMD Athlon II X3 450

 

Codename Rana

Specification AMD Athlon(tm) II X3 450 Processor

Package Socket AM3 (938)

 

Brand ID 29

Core Stepping BL-C3

 

Core Speed 798.3 MHz

Multiplier x FSB 4.0 x 199.6 MHz

HT Link speed 1995.7 MHz

Stock frequency 3200 MHz

Chipset

-------------------------------------------------------------------------

 

Northbridge AMD RD9x0 rev. 02

Southbridge AMD SB910/950 rev. 40

Graphic Interface PCI-Express

PCI-E Link Width x16

PCI-E Max Link Width x16

Memory Type DDR3

Memory Size 32768 MBytes

Channels Dual, (Unganged)

Memory Frequency 532.2 MHz (3:8)

CAS# latency (CL) 9.0

RAS# to CAS# delay (tRCD) 9

RAS# Precharge (tRP) 9

Cycle Time (tRAS) 24

Bank Cycle Time (tRC) 33

Command Rate (CR) 1T

Uncore Frequency 1995.7 MHz

DMI Baseboard

vendor ASRock

model 970 Extreme3

DMI BIOS

vendor American Megatrends Inc.

version P1.40

date 03/27/2012

ROM size 4096 KB

---

DIMM # 1

 

DIMM # 2

 

Manufacturer (ID) Kingston (7F98000000000000)

Size 8192 MBytes

Max bandwidth PC3-10700 (667 MHz)

Part number KHX1600C10D3/8GX 

 

JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency

JEDEC #1 6.0-6-6-17-23 @ 457 MHz

JEDEC #2 7.0-7-7-20-27 @ 533 MHz

JEDEC #3 8.0-8-8-22-30 @ 609 MHz

JEDEC #4 9.0-9-9-25-34 @ 685 MHz

DIMM # 3

Manufacturer (ID) G.Skill (7F7F7F7FCD000000)

Size 8192 MBytes

Max bandwidth PC3-10700 (667 MHz)

DIMM # 4

Manufacturer (ID) Kingston (7F98000000000000)

Size 8192 MBytes

Max bandwidth PC3-10700 (667 MHz)

 

The memory is installed in 0,1 banks for G.Skill and 2,3 banks for Kingston.

 

The G.Skill 2x8GBs are nominally rated 1333 9-9-9-24 while Kingston 2x8GBs support 1600 with 10 CAS. Still, the specs for Kingston at lower speeds look identical to G.Skill, thus the memory chips should be compatible at those lower speeds(1333 and less), should they not?

The main question remains, where do I find the memory limitations for particular AMD CPUs? 

 

I finally solved the issue myself by downclocking RAM to 800Mhz and enabling single channel mode. After that, I went up to 1066Mhz and so far so good, but I do feel a bit silly going so far below memory specs and using single channel in times of quad channel.

It is very hard to find good information on how much RAM each AMD CPU supports. The best I could find was here:

http://support.amd.com/us/kbarticles/Pages/ddr3memoryfrequencyguide.aspx

quad channel???

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PhenomII 1100T// Asus Sabertooth R2.0 // 2X HD5850 CF //8Gb of 1866Mhz ram, H50 cooling, HX850W psu all stuffed into a NZXT Phantom case.


Was a member of AMD Processer forum since 2008. Last post count 1818.

X79 MBs require quad channel memory

X79 is Intel, AMD's only use dual channel outside of the server market. Quad channel memory access outside of that is about as useful as...32GB RAM, there are much better things to spend your money on that will net you a greater speed increase.

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Crosshair IV Formula, Phenom II x4 965 w/ Corsair H60, 8 GiB OCZ Platinum DDR3 1600, XFX HD 7970 Ghz, 512GB Vertex 4, 256GB Vector, 240GB Agility 3, Creative X-Fi Titanium w/ Creative Gigaworks S750, SeaSonic X750, HP ZR2440w, Win 7 Ultimate x64

I concur that for most uses, 32GB is overkill, even though Windows and Ubuntu use the RAM as cache quite nicely, and you get the effect of a RAMdisk for your most used applications.

However, when doing large scale data analysis, where I am currently IO bound not CPU bound, it makes sense to put as much of the data into RAM.

In fact, I could really use about 128GB RAM, but that would require going to registered ECC memory and server MB.

Back on topic, I remember that Toms Hardware did some tests a few years ago comparing single channel and double channel perfomance and found that a slight OC was more effective than going from single channel to double channel. 

Still, I would like to see better disclosure on memory speed constraints.