Solved

Faster to have all 1333mhz memory or mix and match 1333 and 1066mhz for a higher GB?

Posted on 2011-03-23
5
814 Views
Last Modified: 2013-11-10
Hi All,

Upgrading a machine with 4 GB 1066mhz memory, adding 8 GB 1333mhz.  There is enough DIMM slots to run all 12 GB.  Is there a rule of thumb as to if it will run better with 12 GB (but presumably it will auto-set them all down to 1066mhz) or if it would run better with just the 8 GB at 1333mhz?

We could also find 8 GB 1066mhz but that seems to have little point if it can just underclock automatically.

Thanks!
0
Comment
Question by:Jsmply
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
5 Comments
 
LVL 2

Accepted Solution

by:
mklp earned 125 total points
ID: 35205174
Hello Jsmply,

As a rule of thumb, the simple answer is that additional RAM will improve performance more than increased clock speed of the RAM. That said, the fun begins and you might also consider the following:

1) Yes, the BIOS will cripple the 1333 stuff back to 1066 because of the 4 GB, but what is the FSB (Front Side Bus) speed of the system? Memory management is handled by the Chipset  If the FSB is 533 MHz anyhow (1066 RAM) then no harm no foul concerning overall system performance.

2) When memory (the silicone) is fabricated, the chips are tested to see how many clock cycles that particular chip can handle. Although it may be engineered to come out at 1333, if it has errors at that speed but runs fine at 1066 then, voila, you've got a brand new shiny 1066 chip. Thus if 1333 is running at 1066 it will simply last forever and not be prone to errors. Kind of like running a 100 watt lightbulb at 60 watts on a dimmer. The tungsten will last forever.

3) Concerning using only the 8 GB of 1333 vs all 12 GB mixed (thus running at 1066 because of the first 4 Gigs) in general the more RAM the merrier as mentioned above. BUT, what is the machine used for and how much RAM is generally required for the applications? If the 4 GB left you short and thus paging to the disk a lot, then any addition will help but possibly not as much as you would like it to. If it's video editing, then as much as possible is probabaly best, but if it's office applications, browsing, and games (presuming the 8 GB is enough to satisfy all of what you may have open at the same time) then, (again presuming the system supports 1333) 8 GB at 1333 MHz may show better performance. If you've got multiple GB databases you're trying to crunch, then more is merrier no matter what the clock speed.

4) You should check the motherboard, processor, and chipset specs to make sure that you don't need to be running your RAM in matched pairs (or "sets"). Let's say you have 4 slots and two are now occupied with 2 x 2 GB sticks. You're going to add 2 x 4 GB sticks to the other 2 slots to make your 12 GB. That's fine. However if your system wants "matched pairs" then you want to know some specific stuff. Are slots 1 and 3 along with slots 2 and 4 the "pairs" or is the motherboard configured so that slots 1 and 2 are a pair along with slots 3 and 4 for the other pair? In any case, if "matched pairs" are required for optimal perfomance, mixing the speed (and even the brand) can cause obscure headaches. It's always best to use the same brand and clock speed when pairs are required, at minimum in their respective "pair" slots, but ideally throughout. In other words, don't mix a Corsair 1333 with a Micron 1333 and call it a "pair". And NEVER put different clock speeds or sizes together in the same "pair" slots no matter what the brand.

5) You're not likely to disable the system if you don't follow 4 above because the BIOS and Chipset will likely handle it for you, but your shiny new 8 GB might just make things run slower (and maybe funkier) than when you had only 4 GB configured properly.

6) I would be inclined, if you really need (or just want) 12 GB, and want it to perform, to grab another 4 GB of 1333 to replace the 1066. This again presumes the system will handle it. Check first to make sure that the BIOS will recognize it, and then check the motherboard and Chipset to see if the 1333 is even going to help it. The system won't reject the 1333 because of the lightbulb analogy above, but if the SYSTEM is going to only run it at 1066, then putting 1333 in it will never make it "1333" because the system won't handle it.

7) This should really have been number 1 in my answer because it might have saved you a lot of reading. Please tell me you're running a 64 bit OS of some flavor. If you're on 32 bit XP, then all of the above is for naught. You can shove as much as you want into the slots and a 32 bit OS is only ever going to use "about" 3 GB. And I do mean "about". There is no hard rule because it's dependent on factors other than just the OS. 64 bit XP or Win 7 should be happy with as much as you can throw at them, one last time, dependent on the system (hardware). :-)

Hope this helps,
mklp
0
 
LVL 70

Assisted Solution

by:garycase
garycase earned 125 total points
ID: 35205578
A couple of thoughts ...

(1)  The system can't run RAM at differing speeds, so as you've already surmised, it will run ALL of the RAM at 1066 if you mix modules of the two speeds you've indicated.

(2)  It MAY run at the slower speed anyway -- even if you install all 1333 modules.    This depends on what the motherboard does to compensate for the high bus loading with 6 installed modules.     I'm assuming from your comments that you're using a motherboard that (a) uses unbuffered RAM, and (b) has 6 memory slots.     If this is the case, it's NOT a good idea to run with 6 installed modules.     If you're using a board that supports dual channel RAM, I'd limit the installed modules to 4;   if it's a triple channel board, I'd limit it to 3 installed modules.    Your memory will be FAR more reliable with this configuration.    If you want a large amount of RAM, use 4GB modules.
0
 
LVL 11

Assisted Solution

by:SemperWiFi
SemperWiFi earned 125 total points
ID: 35205774
@ Jsmply - As you can see, answers on this subject can be quite lengthy. There is certainly some good information posted above. But the one rather important item and seems to be currently missing from this thread. This is a bit of information from you concerning what is the primary use for this system?

The basics behind how RAM works requires all of the modules to be match in operation. So, yes, since it makes most sense to think faster modules can more easily run slower than the reverse, all BIOS coding will relegate all modules to the lowest denominator. This not only includes speed, but latency settings as well. The question is, does this really matter to you?

Some processes perform best with a lot of memory while many don't use very much in terms of memory resources and therefore benefit more greatly by having more speed (or faster memory). Habits can also play a factor; do you use a lot of open applications at a single time ensuing a collective saturation of resources?

The simple way for you to sort out which is best for you. Start with the smaller amount of faster memory. Run the processes which are most intensive on your machine.... is the your memory saturated? If yes, is it sustained or just a quick blip? If the memory does not get saturated for a sustained period of time then you are not running processes which are memory intensive and will therefore benefit more greatly by an increase in memory speed.

On the other hand, if you find that your system memory is pegged about 85% utilization while running your system as you normally do then it would be a performance increase to add more RAM to the setup. Of course this is best done by using matched modules at the highest speed supported by your platform. However, 1333 vs 1066... the honest answer, you'll never feel that behind the mouse. The difference will only become apparent in benchmarks or when running sustained processed which are time and/or action sensitive.
0
 
LVL 46

Assisted Solution

by:Craig Beck
Craig Beck earned 125 total points
ID: 35207390
Never mix memory speeds - end of!

You will be better using the 8GB at 1333Mhz and having a stable system.
0
 

Author Closing Comment

by:Jsmply
ID: 35208671
Thx all!
0

Featured Post

How Do You Stack Up Against Your Peers?

With today’s modern enterprise so dependent on digital infrastructures, the impact of major incidents has increased dramatically. Grab the report now to gain insight into how your organization ranks against your peers and learn best-in-class strategies to resolve incidents.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Does your iMac really need a hardware upgrade? Will upgrading RAM speed-up your computer? If yes, then how can you proceed? Upgrading RAM in your iMac is not as simple as it may seem. This article will help you in getting and installing right RA…
This article outlines why you need to choose a backup solution that protects your entire environment – including your VMware ESXi and Microsoft Hyper-V virtualization hosts – not just your virtual machines.
Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an antispam), the admini…
Finding and deleting duplicate (picture) files can be a time consuming task. My wife and I, our three kids and their families all share one dilemma: Managing our pictures. Between desktops, laptops, phones, tablets, and cameras; over the last decade…

739 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question