Issue with Mixed RAM

[izaakski]

Hi. Recently I brought a second 8gb ddr 3 kit of RAM. Installed them and they worked fine. Yesterday i did a bios upgrade because for some reason, the bios was not saving my OC settings. After the bios update the PC would not boot at all. It was stuck in a infinite boot loop, restarting every couple seconds with no display and i could not get into the bios. I immediately thought something went wrong and i had bricked the mobo. Luckily it worked fine with one stick of ram. So after some experimenting ive found that it works with up to 3 sticks of ram but the 2 pairs cannot be in matching slots, and with all 4 sticks it doesnt boot even though this worked before the bios upgrade. I think the problem is because they 2 kits of ram are different they are not working together in dual channel mode.

 

Is there any way to force the mobo to run in single channel mode and is there any real performance difference doing this. Or would it be best to get another kit that matches what i already have. 

 

Mobo: Gigabyte Z68AP-D3 rev 2.0 (Was bios version FD no version UA9)

RAM kit 1: Kingston Hyper X 2x4GB (DDR3 1600 CL9 @1.65v)

RAM kit  2: Crucial Ballistix Sport 2x4GB (DDR3 1600 CL9 @1.5v)

CPU: 2600k

[NeoFrux]

To disable multiple-channel mode, you'll want to disable the Channel Interleaving and Bank Interleaving options in the Advanced Memory Settings menu in the BIOS. The performance difference I think has been quoted at around 5% between single-channel and dual-channel mode, and less going to quad-channel. This may or may not work out, but I think I know what's going on here.

 

Your first kit, the Kingston HyperX, is rated at 1.65V, while the second kit, the Crucial Ballistix Sport, is rated at 1.5V. AFAIK, it's not possible for the BIOS to independently set the voltage for both of these kits, so it's going to have to be that you disable XMP and run at DDR3-1066/1333 at 1.5V, or manually set the voltage to 1.65V. However, the Crucial kit isn't rated at 1.65V, so you may encounter issues there as well. So the safest bet is just to disable XMP. It's worth noting, too, that when all banks are populated, some motherboards have difficulty providing consistent voltage to all modules, so if you have trouble even at 1.5V, try 1.55V instead to see if that straightens it out.

 

The performance impact of dropping down from -1600 is going to be larger than the performance impact of going from multi-channel to single-channel, however. So if you're stable at 1066/1333, I'd suggest re-enabling the interleaving options to regain a bit of that performance. Not that it's a huge difference anyway, mind you.

[0x1e]

52 minutes ago, izaakski said:

Yesterday i did a bios upgrade because for some reason, the bios was not saving my OC settings. After the bios update the PC would not boot at all. It was stuck in a infinite boot loop, restarting every couple seconds with no display and i could not get into the bios. I immediately thought something went wrong and i had bricked the mobo.

 

44 minutes ago, Runefox said:

<Snip>

 

Do as @Runefox said and see if that works.

 

Also, don't use a saved overclocked setting on a new bios. Some options will be added, others taken away and some tweaked.

Using the same settings can result with issues. When upgrading a bios you should:

Reset to default, Flash, Restart, Unplug machine, Remove battery, Hold power button for 5 seconds 3 times, Put battery back in, Plug machine in. Then start your bios from scratch. Delete old profiles.

 

And to add to above, you will use the slowest highest voltage for mixed ram. So 1600Mhz @ most lax timings @ highest volts. However you have a big gap. 1.65 vs 1.5 , It's best to find the medium.

[izaakski]

Thanks for the suggestions but no luck. I've tried turning off channel interleaving and bank interleaving and underclocking to 1066mhz with 1.5 or 1.65 volts and still not even booting. XMP was turned off from the start.