I've got a new build on the way but currently will only be running 8 gig of ram. Should I expect noticeably faster cpu crunching times running 16 gig vs 8 gig?

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231311
Ram

Machine will be running:

http://www.newegg.com/Product/Product.aspx?Item=N82E16819103913&nm_mc=TEMC-RMA-Approvel&cm_mmc=TEMC-RMA-Approvel-_-Content-_-text-_-
Processor

http://www.newegg.com/Product/Product.aspx?Item=N82E16813131655&nm_mc=TEMC-RMA-Approvel&cm_mmc=TEMC-RMA-Approvel-_-Content-_-text-_-

750w power supply[/url]

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Executive Director GPU Users Group Inc. -
brad@gpuug.org

8 Gig should be fine. What makes more difference is how fast you drive your RAM. Are you planning on using a GPU? A modern GPU will out crunch even the best processor by a wide margin, but even a GPU will benefit from faster RAM.

Steve

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Warning, addicted to SETI crunching!
Crunching as a member of GPU Users Group.
GPUUG Website

8 Gig should be fine. What makes more difference is how fast you drive your RAM. Are you planning on using a GPU? A modern GPU will out crunch even the best processor by a wide margin, but even a GPU will benefit from faster RAM.

Steve

Yep running a GTX 465 currently. Also running a 64g SSD to boot off of with two 1TB SATA drives in a Raid for backup/storage.

Could you elaborate on 'should be fine?' I'm more interested in fast performance than 'it'll do' if you know what I mean.

/noob comments.

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Executive Director GPU Users Group Inc. -
brad@gpuug.org

8G of ram for a Seti machine is overkill. If you want a screaming fast machine stay with one set of ram not filling all slots. Like on my tri channel ram machines I can get more memory speed if I have only one set of 3 memory chips then running 2 sets. Now if you get into overclocking you can really get a lot out of some of them memory sets.

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Every SETI@home or Astropulse task uses only 25-30 MB RAM as you can see in Windows Task Manager
so for AMD Phenom II X6 you can count by yourself:
6 * 30 = 180 MB + some "BOINC use" = ~200 MB total

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- ALF - "Find out what you don't do well ..... then don't do it!" :)
 

The SETI@Home client uses up to 96MB per task, most hover around 64MB per task. Even if you have an 8 core system with HyperThreading, you'll only average around 1GB of RAM used for 16 threads.

Having more RAM won't help at all, but if the CPU can access the RAM faster, that's more important to overall crunching speed. E.g. Using DDR3 1600MHz memory is better than DDR3 1333MHz memory. Using DDR3 1600MHz CAS 7 is better than using DDR3 1600MHz CAS 9.

8 gig as has been said is plenty for SETI. My system is a bit extreme, and has 12 Gig. It's not the amount of RAM I have that makes it fast, it's that I'm running the RAM at 1925 MHz, the processor at 4.25 GHz, and the two GTX 480's at 865 MHz with the GPU RAM running at 1990 MHz. The 12 Gig of RAM helps me with video editing, Photoshop, or running multiple programs at once, but is not needed for SETI.

Steve

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Warning, addicted to SETI crunching!
Crunching as a member of GPU Users Group.
GPUUG Website

Going to 16gb will make pretty much zero difference to crunching.

Ram is only an issue if you don't have enough. How much is enough? The basic Operating System, plus whatever tasks (Boinc and anything else) you are running. If it's only S@H, like the guys said that's about 64mb per task, and a bit left over for disk caching etc.

Once you have enough RAM in the system so nothing ever needs to be paged out to hard disk, then adding more doesn't help. Being short of RAM, and the system needing to page memory to hard disk, now that WILL slow you down big time.

Like the others suggest, speed of memory, and having it working as double (or triple) channel does make a difference, and not having all the slots full man mean less electrical loading on the data bus, and allow a few more Mhz of overclock before things go flaky.

From experience, my Q6600 crunches about 10% better with the Ram in dual channel, compared to single. That's just changing from a single 2gb stick to 2 X 1gb sticks, no other change. Dropping the memory to 1 x 1gb stick made no difference to S@H, (from 1 x 2gb) but the system slowed down under other apps as it ran low on RAM.

Ian

Ahh gotcha, thanks for the info everyone ^^

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Executive Director GPU Users Group Inc. -
brad@gpuug.org

Just a note..

On my Intel Core2 Duo E7600 system the optimized S@h Enhanced 6.03 (AK_v8b_SSSE3x) use ~ 33 MB average system RAM, ~ 41 MB peak at start.

You will have a 64bit OS? IIRC, 32bit Windows OS see max 3 GB system RAM, no matter how much installed.


- Best regards! - Sutaru Tsureku, team seti.international founder. - Optimize your PC for higher RAC. - SETI@home needs your help. -

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My Core I7 running 8 instanced of Rosetta@home, runs perfectly. I only have 8 gigs of ram in it, running Windows 7, and I have 0 problems. 8gb should be enough for anyone really

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I ran 8 CPU as well as 1 or 2 GPU tasks on my i7-860 Win 7 HTPC machine without any issues while having only 4GB of ram. I think I saw close to 2GB in use at one point, but I was doing a lot of other things at the same time.

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SETI@home classic workunits: 93,865 CPU time: 863,447 hours
Join the [url=http://tinyurl.com/8y46zvu]BP6/VP6 User Group[

Maybe one more little note.. ;-)

On my AMD Phenom II X4 940 BE with 4x GTX260..
2x 2 GB system RAM installed, WinXP 32bit: only 2.25 GB free for usage (normally 3 GB, but every GPU reduce system RAM).

Every S@h Enhanced opt. CPU app ~ 33 MB, stock S@h Enhanced 6.09 cuda23 app ~ 110 MB (AFAIK, opt. CUDA app (which is slower on my systems) use less system RAM - IIRC ~ 75 MB) -> so ~ 600 MB, IIRC whole RAM usage was ~ 800 MB (only crunching).


- Best regards! - Sutaru Tsureku, team seti.international founder. - Optimize your PC for higher RAC. - SETI@home needs your help. -

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As posted above, Seti dose not need a lot of ram. And thats ok if all you do is run Seti. But My crunchers get used for other things. Back when I got my old P4 I was allways running out of memory just opening windows when I was doing photo editing. After I put 2 gigs of ram in that ended that problem.
So when I bought this i7 I knew it was going to be used a lot doing photo editing And othet memory intensive things. In not sorry for one second I had 12 gigs of DDR3 memory put in.

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[/quote]

Old James

several projects (WCG, primaboinca, and Yoyo) have sub projects that require at least 1Gb of RAM for each WU. Not having adequate RAM for those creates a load on your HDD and makes it very noisy

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In a rich man's house there is no place to spit but his face.
Diogenes Of Sinope

In not sorry for one second I had 12 gigs of DDR3 memory put in.

I didn't think that Vista 64 saw that much?

Why not? It's 64bit.

http://msdn.microsoft.com/en-us/library/aa366778(v=vs.85).aspx

Just a note..

On my Intel Core2 Duo E7600 system the optimized S@h Enhanced 6.03 (AK_v8b_SSSE3x) use ~ 33 MB average system RAM, ~ 41 MB peak at start.

You will have a 64bit OS? IIRC, 32bit Windows OS see max 3 GB system RAM, no matter how much installed.


- Best regards! - Sutaru Tsureku, team seti.international founder. - Optimize your PC for higher RAC. - SETI@home needs your help. -

Win 7 64 Enterprise is what I've been told. Not sure if it's Vista or 7 but for sure is 64B. Will confirm in a bit.

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Executive Director GPU Users Group Inc. -
brad@gpuug.org

32-bit Windows can see 4GB RAM max. In fact it's a bit less in reality for some reason I can't remember.

Hence 32-bit (32^4).

32-bit Windows can see 4GB RAM max. In fact it's a bit less in reality for some reason I can't remember.

Hence 32-bit (32^4).

Because everything that is on the bus requires a way to address it. So your onboard IDE takes a tiny bit of space. Your onboard sound takes a tiny bit of space. Your USB ports take up a tiny bit of the address space. Your video card's RAM must also exist in the address space.

A 32bit address can hold up to 4,194,304 bytes or "addresses". Subtract all the addresses I mentioned above and more often than not you come up around 3GB usable space for RAM addresses. Sometimes it's 3.5GB, sometimes it's 2.5GB depending on how much space is required by all your devices.

RAM is the last thing mapped into what's left over after everything has been given a part of the address space.

32-bit Windows can see 4GB RAM max. In fact it's a bit less in reality for some reason I can't remember.

Correct. It depends also upon whether you use single or double sided ram sticks.

This would be a hardware issue and not a software issue. Some chipsets can only address up to a certain amount of RAM. RAM manufacturers will often create double-sided RAM sticks when initial yields of chips aren't that high. As manufacturing improves, they can create higher density chips. So that 1GB module no longer needs 16 chips (8 on each side), they can be done with 8 instead.

The confusion is created when a motherboard's chipset is designed to address "banks" of memory. One bank is not always equal to one DIMM slot. A double-sided RAM stick will often occupy two banks of memory in a single slot. If the chipset can only handle 6 banks in 4 DIMM slots, only 2 or 3 DIMMs can be double-sided (if you want matched pairs, then only 2).

I say one double-sided RAM stick will "often" occupy two banks of memory, but there are tricks a manufacturer can use to make a double-sided RAM module appear as a single bank, so it's not always literally true that double-sided is the same thing as a RAM stick with two sides of memory. In fact, the opposite can be true as well: if yields are already high on a high density chip, a RAM stick with chips on one side can also be "double-sided" as specified in the SPD module to maintain compatibility with some chipsets.

This is why some RAM manufacturers have tried to distinguish double-sided from "dual rank" RAM chips.

One example that comes to mind from about 11 years ago is the Intel 815 chipset. It could only support 3 DIMM slots but had logical space for 4 banks. It's maximum RAM capability was 512MB. You could either use 2x 256MB dual rank RAM sticks to occupy all 4 banks of RAM in two slots while leaving the 3rd physical slot empty, or you could use 1x 256MB dual rank and 2x 128MB single rank sticks to occupy all 4 banks of RAM to reach the maximum 512MB supported.

I remember some of the 256MB modules were single-sided but made dual-rank for backward compatibility back then because manufacturing yeilds were already very high on those higher densities. Even if you bought 3x 256MB single-rank sticks, only two would work on the i815 because of the address limitation in the chipset.

[Edit] Or from the Wiki on "ranking" if that was too confusing:

Sometimes memory modules are designed with two or more independent sets of DRAM chips connected to the same address and data buses; each such set is called a rank. Since all ranks share the same buses, only one rank may be accessed at any given time; it is specified by raising the corresponding rank's chip select (CS) signal. All other ranks are deactivated for the duration of the operation by having their corresponding CS signals lowered. DIMMs are currently being commonly manufactured with up to four ranks per module. Consumer DIMM vendors have recently begun to distinguish between single and dual ranked DIMMs.

DIMMs are often referred to as "single-sided" or "double-sided" to describe whether the DRAM chips are located on one or both sides of the module's printed circuit board (PCB). However, these terms may cause confusion, as the physical layout of the chips does not necessarily relate to how they are logically organized or accessed.

JEDEC decided that the terms "dual-sided," "double-sided," or "dual-banked" were not correct when applied to registered DIMMs.

(My emphasis added)