Slower RAM speeds = no POST

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Slower RAM speeds = no POST

Postposted on Sat Oct 30, 2010 10:19 pm

Hey all,
I'm overclocking my Phenom II X6 1055T here, got up to 275MHz HT reference clock. Then I figured ok, the Kingston ValuRAM should be at its limit, time to decrease the multiplier, and so I jacked it down to 1100MHz from 1467MHz. Funny, it didn't POST this time, but when I got the system back up, it would POST just fine at 1467MHz. All DRAM timing values were set to "auto". I tried setting CAS, RAS to CAS, RAS PRE and ACT to 9-9-9-24 (the motherboard actually runs them faster than the SPD recommends, so 9-9-9-24 is actually a step backwards, plus I set the speed to 1100MHz). Still wouldn't get it working at 1100MHz. At this point, I'm thinking something's messed up with my motherboard's memory multiplier. I'm running a ASUS M4A88TD-V EVO/USB3.

EDIT: the MB also automatically increases the voltage for the RAM and I think the CPU too. I just hit 4GHz with 286MHz HT ref, and the RAM still works at DDR3-1525! Then I saw the voltage - a whopping 1.74V. Time to run a memtest and see if it'll hold up. At this rate, I fear the RAM will be limiting my OC.
Mothership: Thuban 1055T@3.7GHz, 12GB DDR3, M5A99X EVO, GTX470+Icy Vision Rev.2@840/3800, Vertex 2E 60GB
Supply ship: Sargas@2.8GHz, 12GB DDR3, M4A88TD-V EVO/USB3
Corsair: Macbook Air Ivy Bridge
Crayon Shin Chan
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Re: Slower RAM speeds = no POST

Postposted on Sun Nov 14, 2010 10:16 am

Reset the BIOS + remove battery?
mikeymike
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Re: Slower RAM speeds = no POST

Postposted on Sun Nov 14, 2010 10:50 am

Crayon Shin Chan wrote:All DRAM timing values were set to "auto". I tried setting CAS, RAS to CAS, RAS PRE and ACT to 9-9-9-24 (the motherboard actually runs them faster than the SPD recommends, so 9-9-9-24 is actually a step backwards, plus I set the speed to 1100MHz).
Your DRAM has multiple SPD timing profiles for different clock speeds. The ones for the slower clock speeds have lower latency. When you switch the multiplier with the settings in "auto," the motherboard is switching to the lower latency profile. You can look at your memory's timing tables using the SPD tab of CPU-Z.

Use manual memory latency and voltage settings and you should be okay.
i7-4770K, H70, Gryphon Z87, 16 GiB, R9-290, SSD, 2 HD, Blu-ray, SB ZX, TJ08-E, SS-660XP², 3007WFP+2001FP, RK-9000BR, MX518
JustAnEngineer
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Re: Slower RAM speeds = no POST

Postposted on Tue Nov 16, 2010 7:05 pm

Since my motherboard exposes a lot more timing settings than the SPD does (according to CPU-Z), I tried fixing every timing number at the one they were (basically what Auto chose, but set manually), and then changed the RAM multiplier. Surely at 1060MHz 9-9-9-24 and the same timing settings elsewhere that worked at 1410MHz, it would boot! But it didn't, even when the SPD says it can run 7-7-7-21 at 1066MHz.

Timings aren't exclusive to the speed at which you run the modules at, are they? I remember I could run DDR266 at 2/2.5/3, so according to that fixing the timings should work.
Mothership: Thuban 1055T@3.7GHz, 12GB DDR3, M5A99X EVO, GTX470+Icy Vision Rev.2@840/3800, Vertex 2E 60GB
Supply ship: Sargas@2.8GHz, 12GB DDR3, M4A88TD-V EVO/USB3
Corsair: Macbook Air Ivy Bridge
Crayon Shin Chan
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Posts: 2237
Joined: Fri Sep 06, 2002 11:14 am
Location: Malaysia

Re: Slower RAM speeds = no POST

Postposted on Tue Nov 16, 2010 10:52 pm

The other thing to watch for is that your RAM speed setting may be overclocked with your processor interface overclock. If you increase the processor interface speed by 20%, you may need to drop the RAM speed setting by 20% to achieve the same actual RAM frequency.
i7-4770K, H70, Gryphon Z87, 16 GiB, R9-290, SSD, 2 HD, Blu-ray, SB ZX, TJ08-E, SS-660XP², 3007WFP+2001FP, RK-9000BR, MX518
JustAnEngineer
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Re: Slower RAM speeds = no POST

Postposted on Wed Nov 17, 2010 7:54 am

I'm reminded at this point how long it is since I overclocked anything :)
mikeymike
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Re: Slower RAM speeds = no POST

Postposted on Wed Nov 17, 2010 7:57 am

JustAnEngineer wrote:The other thing to watch for is that your RAM speed setting may be overclocked with your processor interface overclock. If you increase the processor interface speed by 20%, you may need to drop the RAM speed setting by 20% to achieve the same actual RAM frequency.

Yes, that's what I'm doing. Trouble is, it won't boot, even when I'm using the same timings that worked with the higher than spec (1410MHz) RAM speed.
Mothership: Thuban 1055T@3.7GHz, 12GB DDR3, M5A99X EVO, GTX470+Icy Vision Rev.2@840/3800, Vertex 2E 60GB
Supply ship: Sargas@2.8GHz, 12GB DDR3, M4A88TD-V EVO/USB3
Corsair: Macbook Air Ivy Bridge
Crayon Shin Chan
Minister of Gerbil Affairs
 
Posts: 2237
Joined: Fri Sep 06, 2002 11:14 am
Location: Malaysia


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