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{Solved} I have 2 Options for Ram. Are either of them compatible? Is one option better?

Go to solution Solved by Eigenvektor,
26 minutes ago, AMixOfGeekContent said:

Are ddr type and MHz the only things that matter for compatibility? Or does voltage and CL latency matter?

All of them matter. You can't physically install a different DDR version than what your machine supports.

 

For MHz and CL, the CPU's memory controller can only run at one speed at a time. So if you mix different speeds it'll typically run at the lowest common speed and highest common latency the sticks support. Or it might fail to boot at all. For voltage, basically the same applies. You system will run all slots at the same voltage.

 

Lower CL at the same speed is better. At different speeds you can use the formula CL x 2000 / DR to calculate the latency in nanoseconds. Lower is better.

Hi. I have a Dell XPS 8500 that supports up to 1600MHz ram Ddr3. Are ddr type and MHz the only things that matter for compatibility? Or does voltage and CL latency matter?

 

My current ram says:

2x 4GB 2Rx8 PC3-12800U-11-11-B1 I dunno the voltage. It's double sided.

2x 2GB PC3 10666 7-7-7 @1.65V

 

I'll either buy:

2 of these black-coloured rams: https://www.canadacomputers.com/product_info.php?cPath=24_311_1904&item_id=063710

   CL11   1.50V   1600MT/s

 

Or this red pair: https://www.canadacomputers.com/product_info.php?cPath=24_311_1904&item_id=043120

   CL10  1.50V     1600MT/s   (is lower CL considerably better, even if it's different from my current CL? I'm keeping the 2x4GB ram, taking out the 2x 2GB ram)

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26 minutes ago, AMixOfGeekContent said:

Are ddr type and MHz the only things that matter for compatibility? Or does voltage and CL latency matter?

All of them matter. You can't physically install a different DDR version than what your machine supports.

 

For MHz and CL, the CPU's memory controller can only run at one speed at a time. So if you mix different speeds it'll typically run at the lowest common speed and highest common latency the sticks support. Or it might fail to boot at all. For voltage, basically the same applies. You system will run all slots at the same voltage.

 

Lower CL at the same speed is better. At different speeds you can use the formula CL x 2000 / DR to calculate the latency in nanoseconds. Lower is better.

Remember to either quote or @mention others, so they are notified of your reply

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13 minutes ago, Eigenvektor said:

All of them matter. You can't physically install a different DDR version than what your machine supports.

 

For MHz and CL, the CPU's memory controller can only run at one speed at a time. So if you mix different speeds it'll typically run at the lowest common speed and highest common latency the sticks support. Or it might fail to boot at all. For voltage, basically the same applies. You system will run all slots at the same voltage.

Okay thanks. I guess I'll buy the boring-looking ram, since its CL Timing is the same as the ram I'm gonna mix it with (afaik, correct me if I'm wrong). Less chance of incompatibility issues.

And the store's return policy is good, too. Free return shipping labels and all. In case anything goes wrong.

 

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1 minute ago, AMixOfGeekContent said:

Okay thanks. I guess I'll buy the boring-looking ram, since its CL Timing is the same as the ram I'm gonna mix it with (afaik, correct me if I'm wrong). Less chance of incompatibility issues.

And the store's return policy is good, too. Free return shipping labels and all.

Shouldn't make too much of a difference outside of benchmarks in any case. And if the price it's showing me is correct (I'm in the EU) it's also 50% cheaper.

 

PC3-12800U is another name for 1600 MT/s. 11-11-B1 should be the latency. You can use CPU-Z to check. Since you've got it mixed with slower RAM the speed it's currently running at is probably lower. You might want to check it on its own. Note that CPU-Z shows physical clock speed, so 800 MHz for 1600 MT/s (marketed as 1600 MHz).

Remember to either quote or @mention others, so they are notified of your reply

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Use CPU-Z to get the details of your current memory.

 

I don't know what generation that is and what processor you have.. it matters. From some generation, some Intel processors only support DDR3L or DDR4  (not both at same time). 

DDR3L is low voltage DDR3 - it runs at 1.35v by default, but with XMP enabled up to 1.5v is allowed.  But if your processor is one of these that like DDR3L only, the processor won't be happy with 1.65v on memory and can even be damaged.

 

Now, you have the frequency (1333 Mhz, 1600 Mhz, 1866 Mhz) , you have timings (vary with frequency, lower timings is better) and you have working voltage.

Any stick will work at the advertised frequency but will also work at lower frequencies.

So for example, a 1866 Mhz stick will run at 1600 Mhz or 1333 Mhz or 1066 Mhz - it's sold at 1866 Mhz because that's the maximum it can do.  Such ram stick may need 1.65v to work at 1866 Mhz but may only need 1.5v to run at 1066 or 1333 Mhz and possibly even at 1600 Mhz - it really depends on the chips used and what profiles the manufacturer puts in the chip.

Here's a picture from SPD tab in CPU on my computer - it's DDR4 memory but same stuff applies :

You can see that 1.35v is required to run at 3200 Mhz (2 x 1600, XMP-3200 profile)  but the sticks can function just fine with 1.2v at lower frequencies like 2133 Mhz (the standard JEDEC 1066 Mhz presets)

image.png.591e2057823a2cf72f90365c9166fe6e.png

 

HWInfo64 is even more thorough than CPU-Z, it gives much more details about RAM installed, what frequencies it can run on and so on. It's free, download it and use it.

 

You don't have to worry too much about the timings, just make sure the sticks you get will support the same voltage as the sticks you have now.

Frequency also matters little. If you find something super cheap at 1333 Mhz, feel free to buy it - if you have 1600 Mhz sticks now, they'll be downgraded and will run at 1333 Mhz - there will be a small performance loss but probably barely noticeable. You'll get much more performance increase by having more memory.

 

 

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1 hour ago, mariushm said:

Use CPU-Z to get the details of your current memory.

 

I don't know what generation that is and what processor you have.. it matters. From some generation, some Intel processors only support DDR3L or DDR4  (not both at same time). 

DDR3L is low voltage DDR3 - it runs at 1.35v by default, but with XMP enabled up to 1.5v is allowed.  But if your processor is one of these that like DDR3L only, the processor won't be happy with 1.65v on memory and can even be damaged.

 

Now, you have the frequency (1333 Mhz, 1600 Mhz, 1866 Mhz) , you have timings (vary with frequency, lower timings is better) and you have working voltage.

Any stick will work at the advertised frequency but will also work at lower frequencies.

So for example, a 1866 Mhz stick will run at 1600 Mhz or 1333 Mhz or 1066 Mhz - it's sold at 1866 Mhz because that's the maximum it can do.  Such ram stick may need 1.65v to work at 1866 Mhz but may only need 1.5v to run at 1066 or 1333 Mhz and possibly even at 1600 Mhz - it really depends on the chips used and what profiles the manufacturer puts in the chip.

Here's a picture from SPD tab in CPU on my computer - it's DDR4 memory but same stuff applies :

You can see that 1.35v is required to run at 3200 Mhz (2 x 1600, XMP-3200 profile)  but the sticks can function just fine with 1.2v at lower frequencies like 2133 Mhz (the standard JEDEC 1066 Mhz presets)

image.png.591e2057823a2cf72f90365c9166fe6e.png

 

HWInfo64 is even more thorough than CPU-Z, it gives much more details about RAM installed, what frequencies it can run on and so on. It's free, download it and use it.

 

You don't have to worry too much about the timings, just make sure the sticks you get will support the same voltage as the sticks you have now.

Frequency also matters little. If you find something super cheap at 1333 Mhz, feel free to buy it - if you have 1600 Mhz sticks now, they'll be downgraded and will run at 1333 Mhz - there will be a small performance loss but probably barely noticeable. You'll get much more performance increase by having more memory.

 

 

Thanks.

I had to look up my ram's model number (the original 2x 4GB that came in the pc), because I have Ubuntu. I managed to open CPU-Z, but a lot of info was missing. I tried an Ubuntu alternative, CPU-X, but it didn't show voltage. I tried a terminal command, but again, mine wasn't showing voltage. lol.

But I found out it's 1.5V, which is the same as the ram I just order. Whew!

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