Troubleshooting help

[Niles P]

I've just put together a new system, but my skills and knowledge in this department is quite limited, meaning that I barely managed that much (requiring the help of manuals and some googling) but lack the insight to efficiently troubleshoot my current issue. (Also I apologize in advance for any terminological mistakes etc).

I have a MSI Z270 SLI PLUS, an i5 7600K, and Corsair Vengeance LPX 3200 mhz 2x8 gb powered by a Corsair RM550X psu.

The system works fine and appears stable so far but with an important caveat. The memory runs at the default 2133 speed, and if I try to activate XMP (or manually set it to 3200 with everything else auto) the system fails to boot and after a restart gets me back into BIOS where I can turn off XMP. The same thing happens if I activate OC Genie but without doing anything else. I had some time yesterday after work to experiment with raising the speed step by step yesterday and at 2666 (again everything else auto since I don't know that much) everything seems stable although I haven't run memtest86 to check for errors (I though I'd try pushing it further tonight).

MSI support suggest to remove the CPU and check the cpu pins to see if there's any damage. I'd rather not though since that would present another opportunity for me to mess things up (which is what happened to my old system in moving it from one case to another), and to me it sounds counterintuitive that there would be something wrong with the CPU if the system runs fine on default speeds (although admittedly intuition can be quite unreliable when you possess very limited knowledge).

So to my question - is it possible to say what the odds are that the CPU (or some other part) is damaged and needs to be RMA:d? If it is damaged, is the only consequence not being able to run things at full/OC speeds or can there be more malfuncitons down the line even at default sppeds? I'm trying to decide whether I can stick my head in the sand and at worst have to live with the memory running on less than full speed (if it doesn't get fixed in a bios update) or whether I should try to find out now whether there is anything damaged so that I can return it while I still can.

(MSI says that they've tried the exact memory I have at 3200 with the motherboard and that it should be working but Corsair doesn't seem to list any MSI Z270 boards as compatible with the memory. I've made sure to use the rights slots according to the MSI manual).

Is there any less "invasive" troubleshooting steps to take before removing the CPU?

Thanks

Niles

 

[Niles P]

tl;dr.

I can't activate XMP or manually set my DDR4 memory to its rated speed (3200) (or activate OC genie). It seems to run fine set manually to 2666. I've received advice that it might be a bent pin on cpu socket.

Is there any tests that I can run to confirm that the system is stable as is (bent pin(s) or not) so that I can stick my head in the sand and not have to remove the cpu (risking damaging something in the process) assuming that I'm fine with not being able to run at full speed. And/or is there any way to determine the probability that bent pins are the root cause without removing the cpu to check?

 

[Bouowmx]

About manual memory tuning: DDR4 transfer rates higher than 2666 MT/s typically need memory voltage 1.35 V instead of normal 1.2 V. Higher transfer rates also need increased timings, but I think motherboard is smart enough to figure that out.

About troubleshooting: Test with individual memory modules and slots. Use process of elimination to determine whether memory or motherboard is faulty, and request replacement from retailer. If replacements do not work properly, your CPU sample has poor memory controller.

I can't comment on the efficacy of today's automatic overclocking: Gigabyte GA-H55M-UD2H used very high voltage (approx. 1.4 V) on a Intel Core i7-870 overclocked to 3652 MHz (166 MHz × 22) that works fine at normal voltage (1.2 V).

 

[BonzaiDuck]

Sometimes people can be confused by the BIOS menu's options.

Only in exploring a sieve of possibilities -- nevertheless useful in understanding our world -- my Z170 board in earlier releases had an older BIOS, and wouldn't run with RAM at speeds higher than 2,666. When I finally bought the board in retail shrink, the BIOS that shipped with it opened up a compatibility advantage with 3,200 or even higher.

Sometimes, the configuration screens in BIOS allow selection of an XMP profile, but you have to choose the actual SPEED in a separate item. In my Z68 systems, this would affect the board's default bCLK speed or memory-multiplier -- I'm vague about the details, but it could happen.

Further, manually tweaking XMP RAM at XMP speeds could be a loser or just suboptimal. There are the four basic timings, and then there are secondary timings. Good XMP RAM will aggressively set these secondary timings to make the RAM work best at its top spec speed. If you attempt to set the RAM speed manually and even input the spec timings without using the XMP profile, the secondary timings may still default to the 2133 default, or in some related way remain suboptimal.

Once you set up the RAM properly at stock CPU settings and XMP specs, AND if you needed and installed a BIOS update and flash, AND they still don't work properly -- test one at a time to locate the defective module, and arrange for an RMA.

Also, I'd say to recheck the QVL list and the RAM-maker's configurator to certify that they work with that motherboard. Even if the QVL list only includes models rated at non-OC speed, it should be part of a "model-line" that includes XMP kits with similar model code differing at most by digits specifying the speed and CAS. You should be able to find a match between the kits compared with certain parts of the model-code. For instance, GSKILL's suffixes -- like "GBRL" or "GTX" or "GTZ" would indicate the same model-line. You can extrapolate from a QVL list with a certain degree of reliability. RAM-maker configurators to specific motherboards or SIMILAR boards will be more specific about faster or slower models.

For instance -- and I think it was my RAM -- my Sabertooth was not included in the configurator's dropdown option list. But the Sabertooth and Z170 Deluxe or Pro boards are similar, it looked like TridentZ's of a certain model code would work, and customer-reviews confirmed it.

 

[Niles P]

Thank you both for your input. I will try to see if one memory stick works better. Is it worth trying in different slots although the manual specifies which slot(s) to use for one and two sticks respectively?

I found my memory here https://www.msi.com/Motherboard/support/Z270-SLI-PLUS.html#support-mem :

Vendor Model DDR RAM Speed Supported Speed* Chipset Voltage S/D Size 1 2 4 DIMM
Corsair CMK16GX4M2B3200C16R DDR4 3200 3200 Samsung 1.35v SS 8GB √ √

As you can see from the model number, it's 16 gb (2x8), but in the "size" column it only states 8gb even though the 1,2,4 DIMM column specifies 2 DIMM. I don't know what SS means in the S/D column. Does all this mean that I should be able to use 2x8 gb or only 8gb?

Corsair does not list the mobo here http://www.corsair.com/~/media/corsair/download-files/manuals/dram/ddr4-compatibility.pdf.

 

[Bouowmx]

My interpretation: "8 GB" is size per module. "DIMM" column indicates number of modules tested. SS and DS stand for "single-sided" and "double-sided", describing the sides on which the memory chips are located on the module.

I never cared about the qualified memory list. But then, I never significantly exceeded processor's supported memory transfer rates.