X58 triple channel using non-triple channel memory

[MrCaffeineX]

I've got an i7-920 setup (the one in my signature) and I was running a 6GB (3x2GB) Corsair Dominator 1600MHz kit. Since my Ivy Bridge system is now my daily-driver/primary gamer, I'm thinking about relegating the Bloomfield setup to virtual machine sandbox duties and occasional gaming when friends come over.

I want to increase the memory, but let's face it, 24GB triple channel kits are insanely priced and buying two 12GB kits isn't any better. For an experiment, I tried using 3/4 of the Samsung sticks I had in the Ivy Bridge rig to see if they would work in triple channel mode (they are from two dual-channel kits) and so far they seem to be doing fine, though outside of loading a ton of virtual machines or letting it crunch away on Memtest, I'm not sure what else to do to ensure real stability...Perhaps Prime95 or IBT, even though I'm not concerned about the CPU OC's stability?

Was the marketing for triple-channel kits just hype? If I can reasonably expect the system to perform, I can snag another used kit of the Samsung memory for much less than either true triple-channel option.

The other question that I have is about increasing the voltage. I have seen it recommended in quite a few places to bump the voltage to 1.6 or 1.65V if running the system with all six DIMM slots populated. Is this because of the memory needing the extra voltage to maintain stability or because of the memory controller?

These Samsung sticks are currently chugging along at DDR3-1333 8-8-8-22 and 1.25V. This is what the BIOS defaulted to running them at and I don't think it is negatively impacting performance in any way so far. I have seen people online overclocking them to DDR3-2133+ at 1.6 - 1.65V, so I imagine they could handle it, but is it likely that it will be necessary?

 

[dandragonrage]

Doesn't matter how you buy them. You absolutely do not need to get them in a kit.

 

[Ultima99]

For RAM stability Memstest, Prime95 blend test, perhaps Sisoft Sandra RAM benchmarking.

 

[bigdogchris]

I asked about this in another thread maybe a month ago. For example, CompTIA seems to think you cannot buy channel kits and use them for anything but what's advertised. But as some people pointed out, whether you buy a single stick, or in a quad channel kit, all 4 sticks are identical. The computer has no way of knowing?

So to answer your question, you can buy any amount of sticks in any 'kit' combination and run them as you see fit, as long as they are compatible with your motherboard and cpu.

 

[atticus14]

yeah selling them in packages of three is just for marketing purposes. I'm still running on X58 myself and just bought a 8gb stick of a different brand, so I have 8gb Corsair + 2gb + 2gb Gskill.

I will mention that it might pay to check your motherboards info concerning it's ram slots and tri channel compatibility. For example I have an EVGA tri-SLI x58 and it has 6 memory slots, but only 3 specific ones support Tri Channel. I can fill up all slots if I wanted to but it would kick it into Dual Channel mode. I'm not sure if thats common among x58 mobos or not.

 

[HobartTas]

Greetings

For an experiment, I tried using 3/4 of the Samsung sticks I had in the Ivy Bridge rig to see if they would work in triple channel mode (they are from two dual-channel kits) and so far they seem to be doing fine

There is no reason for them not to work.

letting it crunch away on Memtest, I'm not sure what else to do to ensure real stability...

Always a good idea to run Memtest on any memory.

Was the marketing for triple-channel kits just hype?

Mostly yes, I think when X58 came out Anandtech did real world tests with three sticks used and then they re-ran the tests by taking out one of the sticks and just running on the two remaining channels, the difference in performance from memory was about 5% due to the fact that the Intel CPU's have large onchip cache's resulting in less need to access main memory, also around that time (due to the influence of the cache again) faster RAM had less of an impact in performance as well (well it had some impact but the cost of the faster memory was not worth it as it was signifiantly more expensive and the extra cost would have paid for a better video card giving more bang for the buck).

I can snag another used kit of the Samsung memory for much less than either true triple-channel option.

I think this is a better idea as well.

The other question that I have is about increasing the voltage. I have seen it recommended in quite a few places to bump the voltage to 1.6 or 1.65V if running the system with all six DIMM slots populated?

Can't comment about that other than to say do not go over the 1.65 volts as I believe that is the limit for the memory controller and if you go over that you risk burning it out, This was a problem when the X58 first came out as memory used at the time could run as high as 2.0 volts. Because triple channel memory was only to be used for X58 there was none sold running at the 2.0 volt mark so you were always safe buying triple channel but if you bought dual channel you always had to check it wasn't old RAM running at 2.0 volts, shortly thereafter pretty much all RAM had transitioned to 1.65 volt max anyway.

Is this because of the memory needing the extra voltage to maintain stability or because of the memory controller?

I think this is due to originally the X58 chipset only officially supporting 2GB sticks at the time and not the 4GB ones (or was it between 4GB and 8GB sticks? I can't remember exactly). Regardless some people often complain that their machine does not always detect all the memory sticks they have placed into their motherboard.

I asked about this in another thread maybe a month ago. For example, CompTIA seems to think you cannot buy channel kits and use them for anything but what's advertised.

Not true for normal usage (futher explanation follows).

But as some people pointed out, whether you buy a single stick, or in a quad channel kit, all 4 sticks are identical.

They are different but treated as idential for normal usage (further explanation follows).

The computer has no way of knowing?

Explanation:
Actually, it does, apparently AFAIK the difference between say X58 RAM, Z68 RAM and X79 RAM is the fact that the SPD chip on the RAM stick itself could have different settings for XMP memory possibly due to different bus speeds/CPU mulipliers/Ram multipliers or whatever the reason that actually exists for it to have different settings. If you use the the wrong memory the worst that can happen is if (and only if) you want to run at XMP speeds you may have to enter the RAM speed settings in your BIOS manually rather than if say you have the correct memory then the BIOS will automatically read the SPD chip on bootup and set everthing accordingly, for normal RAM speeds (other than XMP speeds) this is not an issue, if you wish you can examine your own SPD settings with CPU-z. This is how the BIOS adjusts for the correct latencies for your RAM as it reads the SPD chip on bootup.

Whether this is true or not I have no real idea but given that manufacturers have to segregate memory into different categories which is something they would not ordinarily do as it would cost them more does tend to support my argument. Also probably the reason "CompTIA seems to think you cannot buy channel kits and use them for anything but what's advertised" is perhaps if people buy the wrong RAM with the specific intention of wanting to automatically run at the high XMP speeds then it probably won't and they don't want the hassle of people RMA'ing otherwise perfectly good RAM.

For example I have an EVGA tri-SLI x58 and it has 6 memory slots, but only 3 specific ones support Tri Channel. I can fill up all slots if I wanted to but it would kick it into Dual Channel mode. I'm not sure if thats common among x58 mobos or not.

Most unusual, I always thought that X58 was 3 memory channels times 2 slots per channel equals 6 slots, there have been some 4 slot Intel MATX boards around but they were still triple channel with the fourth slot also being allocated to one of the channels and slots 5 and 6 physically not present. I'm assuming the "dropping down to dual channel" issue might have something to do with the generic situation of not detecting all the RAM sticks if all 6 slots are populated and this problem was exacerbated further still if all 6 slots were populated with even larger sized sticks.

If you want to know more about this topic I suggest you research it further as this is about the extent of my knowledge about this issue.

Hope this helps somewhat.

Cheers

 

[westrock2000]

I was under the impression the only benefit to buying "kits" was so that all the timing qualities of the sticks would be matched instead of buying memory that all looks to be the same at the advertised speed, but then you realize the numbers are all over the place at other speeds.

 

[Ocean]

I always thought of kits as being for older or defective motherboards that didnt have the ability to synchronize the sticks of ram to the weakest timings, or if they wanted them to be pretty.

if you match up the timings and the frequency, i think its really unlikely that it wont work in dual,triple,quad channel.

 

[bigdogchris]

Explanation:
Actually, it does, apparently AFAIK the difference between say X58 RAM, Z68 RAM and X79 RAM is the fact that the SPD chip on the RAM stick itself could have different settings for XMP memory possibly due to different bus speeds/CPU mulipliers/Ram multipliers or whatever the reason that actually exists for it to have different settings. If you use the the wrong memory the worst that can happen is if (and only if) you want to run at XMP speeds you may have to enter the RAM speed settings in your BIOS manually rather than if say you have the correct memory then the BIOS will automatically read the SPD chip on bootup and set everthing accordingly, for normal RAM speeds (other than XMP speeds) this is not an issue, if you wish you can examine your own SPD settings with CPU-z. This is how the BIOS adjusts for the correct latencies for your RAM as it reads the SPD chip on bootup.Cheers

I think everyone on this board understands what SPD information does. You're long winded explanation of an extremely simplistic topic did nothing to address the original concern regarding channels.

 

[Ocean]

fwiw, windows 7 now has a perfectly fine built in memory tester.

mdsched.exe

 

[bigdogchris]

So I was doing some more reading and the reason manufacturers label memory as a 'kit' is because it's tested as stable for that voltage in packaged configuration.

e.g. You buy a triple channel kit, then add one more identical stick. You may not be able to get the performance rating of the memory, or you could have stability issues.

 

[dandragonrage]

e.g. You buy a triple channel kit, then add one more identical stick. You may not be able to get the performance rating of the memory, or you could have stability issues.

What? If you buy an "identical stick," then there is a 0% chance it will be more unstable than if you'd gotten them all in a kit.

Some motherboards don't play nicely with some mismatched memory, but if your memory is all of the same voltage and you're trying to run it at the slowest speed out of them and it's still not working, it's usually not an issue with your RAM but with your motherboard (or I suppose you could have issues with both). People don't recommend this configuration not because it is incorrect, but because computers are extremely complex and finicky and issues with mismatched memory are most likely going to be ignored by the motherboard manufacturer. It IS their fault, but they are NOT interested in fixing every single problem that people encounter (and it is probably not possible to do so, anyway).

I've spent many years with many computer setups and most of them have run mismatched memory. Rarely is it an issue. Though it was an issue on the Gigabyte Z87MX-D3H I picked up recently, but I swapped that out for an Asus Hero which is doing fine.

 

[ksar123]

To the original poster: I've been running 3 x 8GB sticks (taken from two 16GB dual channel kits) on a Sabertooth X58 for over a year without a single issue. The kits are purely for marketing, the memory in a single/dual/triple channel kit will work in any configuration that your MB supports.

 

[bigdogchris]

What? If you buy an "identical stick," then there is a 0% chance it will be more unstable than if you'd gotten them all in a kit.

It has nothing to do with the sticks and all to do with motherboards, voltage, and memory controllers. Don't kill the messenger, bro.

I've never had a problem with it either, I'm just saying I've read memory manufacturers won't guarantee it to work.