PO3-650 added RAM,now PredatorSense reports a RAM frequency got switched from 4400 MHz. to 2000 MHz.

eponymous

Hello, I have a PO3-650 desktop which came with 2 x 8 GB DDR5-4800 RAM (A-Data/Samsung).

I wanted more RAM, so I added 2 x 16 GB DDR5-5600 RAM from Crucial (CT16G56C46U5.C8D), for a total of 48 GB RAM.

I tested each pair of sticks tested separately using MemTest86, and they showed a RAM Config of 4388 MT/s, and PredatorSense reported a RAM frequency of something like 4400 MHz.

However, with both pairs installed in the system (Crucial 16 GB in DIMM slots 1 and 2; A-Data 8 GB in DIMM slots 3 and 4), the MemTest86 RAM Config drops down to 1994 MT/s, and PredatorSense reports a RAM frequency of 2000 MHz.

Can someone help me understand why the RAM speed drops so much with both pairs of RAM sticks installed vs each pair separately? Is this expected, and can I do anything to improve it?

[Edited the topic title to include the topic issue.]

GAMING6698

https://community.acer.com/en/discussion/714462/po3-650-added-ram-now-predatorsense-reports-a-ram-frequency-got-switched-from-4400-mhz-to-2000-mhz

The drop in RAM frequency from 4400 MHz to 2000 MHz when adding new sticks is likely due to incompatibility between the different RAM modules. Mixing different brands and speeds can cause the system to default to the lowest common speed, which in your case appears to be 2000 MHz.To improve performance, ensure all RAM sticks are of the same specs.

Best solution is that sell either old rams or new RAMs and buy same specs RAM as existing RAM has.

(For best performance need to have same size, frequency, DDR5, Voltage and same CL rate)

GAMING6698

https://community.acer.com/en/discussion/714462/po3-650-added-ram-now-predatorsense-reports-a-ram-frequency-got-switched-from-4400-mhz-to-2000-mhz

The drop in RAM frequency from 4400 MHz to 2000 MHz when adding new sticks is likely due to incompatibility between the different RAM modules. Mixing different brands and speeds can cause the system to default to the lowest common speed, which in your case appears to be 2000 MHz.To improve performance, ensure all RAM sticks are of the same specs.

Best solution is that sell either old rams or new RAMs and buy same specs RAM as existing RAM has.

(For best performance need to have same size, frequency, DDR5, Voltage and same CL rate)

eponymous

Thanks for answering my question. That makes sense, and not knowing too much about the intricacies of RAM, I wasn't aware of this before.

Looking at the CPU-Z JEDEC timings, it shows:

Module Manufacturer(ID) A-Data Technology (7F7F7F7FCB00000000000000000000)
Part number AO2V48UC8W1-BHLS
Size 8192 MBytes
Max bandwidth DDR5-4800 (2400 MHz)
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 22.0-22-22-44-66 @ 1366 MHz
JEDEC #2 26.0-27-27-53-79 @ 1633 MHz
JEDEC #3 28.0-29-29-57-85 @ 1766 MHz
JEDEC #4 30.0-30-30-60-90 @ 1866 MHz
JEDEC #5 32.0-32-32-64-96 @ 2000 MHz
JEDEC #6 36.0-37-37-73-109 @ 2266 MHz
JEDEC #7 40.0-39-39-77-116 @ 2400 MHz
JEDEC #8 42.0-39-39-77-116 @ 2400 MHz

Module Manufacturer(ID) Crucial Technology (7F7F7F7F7F9B000000000000000000)
Part number CT16G56C46U5.C8D
Size 16384 MBytes
Max bandwidth DDR5-5600 (2800 MHz)
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 22.0-22-22-44-66 @ 1366 MHz
JEDEC #2 26.0-27-27-53-79 @ 1633 MHz
JEDEC #3 28.0-29-29-57-85 @ 1766 MHz
JEDEC #4 30.0-30-30-60-90 @ 1866 MHz
JEDEC #5 32.0-32-32-64-96 @ 2000 MHz
JEDEC #6 36.0-37-37-73-109 @ 2266 MHz
JEDEC #7 40.0-40-40-80-120 @ 2500 MHz
JEDEC #8 42.0-43-43-85-127 @ 2633 MHz
JEDEC #9 46.0-45-45-90-135 @ 2800 MHz
JEDEC #10 50.0-45-45-90-135 @ 2800 MHz

The the fastest common speed shared by the two modules is indeed 2000 MHz, as you suggested.

billsey

You might also be looking at apples and oranges. 4400 MT/s is the same as 2200 MHz when in dual channel mode. The 2800 MHz spec you see with CPU-Z is the 5600 MT/s that matches the spec of the new memory. If you remove the original memory rated at 4400 MT/s you should see the new memory able to run at 5600 MT/s using the XMP features in your BIOS. IIRC the chipset drops the maximum speed when in JEDEC mode if four sticks are installed, from 4400 to 4000, which aligns with the 2000 MHz you are seeing.