Upgrading DDR3 ram

[Dazkent 113]

Hello

I had my system built for me back in 2014 (Gigabyte GA-Z87-HD3 motherboard, I7 4770k Running at 4Ghz, GTX770 2GB running Win7), as I didn't feel confident in building one myself. Last year i upgraded to a GTX 970 4GB which I managed to do myself and I have been very happy with peformance running FSX. I have also dabbled with P3D v3 and now V4 has been announced I would like to give this a try.Now  I don't expect to run on max sliders just hopefully smooth performance running a single screen 1920x1080  I have been reading the discussions and have read that 16GB is probably the minimum I should be running and at the moment I just have 8GB.

I have had a look on the motherboard and 2 of my memory slots are occupied so even with my bad maths i gather i have 2x4GB memory sticks. The make of the memory is Corsair Vengeance Pro Silver and the sticker on the side says CMY8GX3M2A1600C9 , so I think it is running at 1600mhz?. The question i have is that i could purchase another two sticks of 2x4GB for a very resonable price giving me 16GB but I also see that memory comes in 2x8GB. I have read that its best to stick to the same brand and speed?

Can  I add a 2x8GB giving me 24GB in total or do all sticks have to have the same capacity?

Hope that makes sense, all of this stuff overwhelms me a bit :(

 

 

[fghdgdfdfgfgf 111]

Id sit tight til you have V4 installed, then act according to your needs.

I get the sense with V4 that if you need more than 8 gigs of system ram then you're probably gonna need more than 4 gigs of video ram. So your upgrading may not stop with system ram.

 

 

re: upgrading memory

I would dispose of your existing memory and install a new 2 x 8GB kit.

 

[stans 702]

On 5/24/2017 at 2:36 PM, Dazkent said:

Can  I add a 2x8GB giving me 24GB in total or do all sticks have to have the same capacity?

I think it is possible to do that, but the new RAM would need to be fully compatible with the old RAM.  Even installing 2 new sticks of supposedly matching RAM does not always work.  I guess it is small variations from one manufactured lot to another that can cause problems. 

I checked the specifications of your motherboard.  The Gigabyte GA-Z87-HD3 uses a dual channel RAM controller, so the CPU will access only two RAM slots at a time.  Populating all four slots could slightly reduce performance.

[Dazkent 113]

Thank you for your replies guys, I think for now I will see what the system requirements are going to be and then maybe go the 2x8GB sticks and remove the current ones. I was interested to read that populating all 4 slots could actually reduce the performance, do you know why this can happen?

As for the graphics card i kind of expect to maybe have to upgrade that too at some point, just as well there is lots of overtime on offer at work

[stans 702]

13 hours ago, Dazkent said:

 I was interested to read that populating all 4 slots could actually reduce the performance, do you know why this can happen?

It depends on the RAM controller on the motherboard.  Dual channel controllers will allow the CPU to access only two RAM slots at a time.  So, if three or four slots are filled and the CPU is looking for data that is on the RAM in the third or fourth slot, it first searches the RAM in the first two slots, then switches to the next two slots, this takes time.  There is also a very, very slight pause as the controller switches between the pairs of slots, it's not much time, but that adds to the time it takes the CPU to retrieve its desired information.  So for a dual channel motherboard, I'd stick to filling the first two slots only unless you have applications that require more RAM than can be handled by two slots.

Motherboards equipped with quad channel controllers do not have to switch between the two pairs of slots, but probably the biggest benefit of quad channel is the increased bandwidth of the RAM channel to the CPU.

[Dazkent 113]

Thank you for the detailed explanation, that makes sense. I have decided to get a couple of 2x8GB ones to replace the 2x4GB ones I currently have

[LRW 42]

On 5/27/2017 at 6:14 AM, stans said:

It depends on the RAM controller on the motherboard.  Dual channel controllers will allow the CPU to access only two RAM slots at a time.  So, if three or four slots are filled and the CPU is looking for data that is on the RAM in the third or fourth slot, it first searches the RAM in the first two slots, then switches to the next two slots, this takes time.  There is also a very, very slight pause as the controller switches between the pairs of slots, it's not much time, but that adds to the time it takes the CPU to retrieve its desired information.  So for a dual channel motherboard, I'd stick to filling the first two slots only unless you have applications that require more RAM than can be handled by two slots.

Motherboards equipped with quad channel controllers do not have to switch between the two pairs of slots, but probably the biggest benefit of quad channel is the increased bandwidth of the RAM channel to the CPU.

I don't think this is completely accurate, or at least not clear.  When the OS wants to read from or write to a given logical memory address, the memory controller will map that logical address to the actual physical location (channel/rank/bank/row/column).  It doesn't sequentially search the RAM (which is, after all, Random Access Memory).

 

[stans 702]

Well, I posted my understanding of how the RAM controller works. 

[Ray Proudfoot 8,925]

PMFJI. I am in a similar position to the OP in that I'm considering my RAM options for P3D v4.

I have the Gigabyte Sniper M5 with 2 x 4Gb Corsair PC3-10700 modules. Using CPU-Z to analyse them they are running at 1866MHz.

My Sniper M5 is also a dual channel board. Am I best removing those modules and getting 2 x 16Gb modules and if so what speed would you advise? Having recently acquired a 1080 8Gb card I think the rest of my system is okay to get decent performance .

The reason I'm looking at 32Gb rather than 16Gb is I have a complex 3rd party aircraft plus lots of addon airports. LM advise 16 for the default P3D.

My system details are in my sig. Thanks.

Edited May 31, 2017 by Ray Proudfoot
Additional info.

[bic 44]

What Stan said...

Convention is that cpu or is it the memory controller only accesses two sticks of ram at one time (except DDR4).  So if it needs to access something on the other two slots (sticks), you have to wait a bit (next interrupt/cycle).  So, it's better to have two sticks of ram performance wise.  

As always, best to check motherboard manufacturer for what they "approve" of.

[Ray Proudfoot 8,925]

27 minutes ago, bic said:

What Stan said...

Convention is that cpu or is it the memory controller only accesses two sticks of ram at one time (except DDR4).  So if it needs to access something on the other two slots (sticks), you have to wait a bit (next interrupt/cycle).  So, it's better to have two sticks of ram performance wise.  

As always, best to check motherboard manufacturer for what they "approve" of.

There seems to be a difference of opinion on whether 4 sticks work efficiently in a dual controller m/b. Why would any m/b manufacturer fit 4 slots if only 2 could be used efficiently? That I don't understand.

I did check the list of recommended RAM but couldn't find what I currently have. I guess speeds have increased. Does that mean I'm best getting the next speed up but no faster as the board can't take full advantage? 2133 has plenty of Corsair options including this:- CMZ16GX3M2A2133C10

But it's only available in 4Gb or 8Gb sticks. There are no warnings about using all 4 sockets. I'd need to do that to get to 32Gb.

[bic 44]

Well, I don't think we will notice the time difference, it's probably sub-microseconds or less, just not as efficient as DDR4.  People writing documents and spreadsheets and browsing would not see the difference.  To us extreme gamers we care about that sort of thing in our pursuit of eliminating stutters and not wanting to see a black tile while waiting for a texture to load.  I do not know if there are hard facts to backup the claim that four sticks do create these issues.

 

To add more confusion, you may want to verify the cas latency as well.  cpu-z should be showing it.  I am refreshing my memory on cas latency, so google has been a good friend.

 

 

 

 

[Ray Proudfoot 8,925]

Thanks for your reply. It does appear to be an area of uncertainty. I will check CAS and reply tomorrow. I know there are faster mobos, memory and CPUs but I'm trying to increase memory without a system rebuild. fps in P3D v3 are fine.

[LRW 42]

I was about to post the same thing as bic.  The memory controller timings are measured in nanoseconds.  When I build a new system I always start with two sticks, but I have no problem with adding two more down the road (which I just did last week).  If I were replacing my existing memory with faster sticks, I'd replace it with two.  If a system is at the point where it's running close to memory capacity then adding two additional sticks will make the system run faster.  That's because there will be less paging to and from swap space.  I don't get hung up over 2 vs. 4. 

Be careful with CAS comparisons.  It directly measure the number of clock ticks, not time.  So faster RAM with higher latency can still be better than slower RAM with lower latency, depending on the actual time interval.  Then, there are optimizations that mitigate the latency.  A controller will issue a command to a memory address and then go do other tasks for the number of clock ticks until the data is ready and then come back.  The controller doesn't sit around waiting for 9 ticks (or whatever the CAS # is).

This isn't a bad little read (http://www.crucial.com/usa/en/memory-performance-speed-latency) although, clearly, Crucial is in the business of selling us faster RAM at a higher price: 

[Ray Proudfoot 8,925]

Thanks Larry. Useful advice and link. The problem I have is I can't add two additional sticks identical to the original 2. The PC was built back in October 2013 and obviously things have moved on.

Here is my question. Is it better to add two 8Gb sticks (total 16Gb) to my existing 8Gb making a total of 24Gb accepting the newer pair will be faster than the originals or...

Replace the existing RAM with compatible Crucial alternatives of 2 x 16Gb (total 32Gb)? The type identified as being best for my G1.Sniper M5 is this:-

CT5572408

DDR3 PC3-17000 • 11-11-11-27 • Unbuffered • NON-ECC • DDR3-2133 • 1.65V • 1024Meg x 64 •

upgrade for Giga-Byte G1.Sniper M5 system.

It is faster but I assume it just slows down to the motherboard speed.