Anyone know if there is anything published that talks about memory managment from a CPU perspective? For example, you have a system with two CPU's, and you put 32 GB of RAM in that system, how does having such a large amount of RAM affect CPU cycles? Does the system run smoother if you have less RAM as long as you still meet the RAM requirments for your user base? Here is an example: CPU Guidance: 1000 Heavy Users would equal two processors (1 CPU for every 500 heavy users). Memory Guidance: 1000 heavy users = 2GB min + (1000 * 5) = 12 GB So for 1000 heavy users, a two cpu system with 12GB of RAM is the suggested configuration. My question is, will using 32GB or RAM result in a system that performs worse than the recommended configuration? Does having more RAM hurt the system if you have to few processors? Any feedback appreciated. J. If it was helpful, vote for it. If it answered your question, mark it as answered. Small thing to do for free help from a strong community :)

Look at the sizing tool. It's there. http://msexchangeteam.com/archive/2009/11/09/453117.aspx "Triton.Deep" wrote in message news:f1f2a323-58c6-4ed0-b272-d19f06e0294d... Anyone know if there is anything published that talks about memory managment from a CPU perspective? For example, you have a system with two CPU's, and you put 32 GB of RAM in that system, how does having such a large amount of RAM affect CPU cycles? Does the system run smoother if you have less RAM as long as you still meet the RAM requirments for your user base? Here is an example: CPU Guidance: 1000 Heavy Users would equal two processors (1 CPU for every 500 heavy users). Memory Guidance: 1000 heavy users = 2GB min + (1000 * 5) = 12 GB So for 1000 heavy users, a two cpu system with 12GB of RAM is the suggested configuration. My question is, will using 32GB or RAM result in a system that performs worse than the recommended configuration? Does having more RAM hurt the system if you have to few processors? Any feedback appreciated. J. If it was helpful, vote for it. If it answered your question, mark it as answered. Small thing to do for free help from a strong community :)Mark Arnold, Exchange MVP.

Thank you Mark. That's a good llink, though it doesn't speak to my question though. Under what circumstances does having more RAM than the recommended amount hurt performance. Or does it ever? I found a link here: http://searchexchange.techtarget.com/tip/0,289483,sid43_gci1328030_mem1,00.html But while it speaks to peformance degradation, it uses 32GB as the "Don't go above" number and leaves out CPU considerations all together which is inline with normal Microsoft recommendations. I think, at this point I'll just have to say that there is no evidence that more RAM hurts CPU performance as long as it's 32GB's or less. Thank you! J.If it was helpful, vote for it. If it answered your question, mark it as answered. Small thing to do for free help from a strong community :)

The calculator gives you guidance on how much memory and processor capacity you need. You can go above it if you want but financial limits will kick in before performance issues happen (which is unlikely even to happen). The trick is to size the server to what you need for current and future needs. It's the same reason that you're not going to waste money on SAS when you just need SATA. It's the same reason you're going to size it for a quad core (whatever) when a dual (again, whatever) core might have done. The much touted "memory performance degradation" thing is a marginal distraction. "Triton.Deep" wrote in message news:c9e51b82-430c-457c-b0b9-68c0bdb95bb3... Thank you Mark. That's a good llink, though it doesn't speak to my question though. Under what circumstances does having more RAM than the recommended amount hurt performance. Or does it ever? I found a link here: http://searchexchange.techtarget.com/tip/0,289483,sid43_gci1328030_mem1,00.html But while it speaks to peformance degradation, it uses 32GB as the "Don't go above" number and leaves out CPU considerations all together which is inline with normal Microsoft recommendations. I think, at this point I'll just have to say that there is no evidence that more RAM hurts CPU performance as long as it's 32GB's or less. Thank you! J. If it was helpful, vote for it. If it answered your question, mark it as answered. Small thing to do for free help from a strong community :)Mark Arnold, Exchange MVP.

Well, what spurred the original thought on this is I have a client that is insisting on a 2 vCPU system with 32 GB's of RAM. To me, with that much RAM the CPU count should be 4 OR with 2 CPU's, the RAM amount should have been lower. 2400 users, the client has not done message profiling for there clients so I'm not entirely sure what the profile is. Started thinking about it, and..well..just ended up going down that path and was curious if anyone had any thoughts about it. Thank you for your time and thoughts, much appreciated. J.If it was helpful, vote for it. If it answered your question, mark it as answered. Small thing to do for free help from a strong community :)

The Product Group invested a lot of resources (just look at the current version number!) in that spreadsheet and it stands up very well to scrutiny in production environments. It would be silly for you not to go through that spreadsheet and run the numbers by the customer. You get a lot of leeway in servers, copies, stores and store sizes and they all affect CPU, memory and disk. "Triton.Deep" wrote in message news:83bfd0b4-a9d4-4b5b-a279-159193d0e093... Well, what spurred the original thought on this is I have a client that is insisting on a 2 vCPU system with 32 GB's of RAM. To me, with that much RAM the CPU count should be 4 OR with 2 CPU's, the RAM amount should have been lower. 2400 users, the client has not done message profiling for there clients so I'm not entirely sure what the profile is. Started thinking about it, and..well..just ended up going down that path and was curious if anyone had any thoughts about it. Thank you for your time and thoughts, much appreciated. J. If it was helpful, vote for it. If it answered your question, mark it as answered. Small thing to do for free help from a strong community :)Mark Arnold, Exchange MVP.

I think perhaps, we are having a failure to communicate. :) Thanks. J.If it was helpful, vote for it. If it answered your question, mark it as answered. Small thing to do for free help from a strong community :)

Well, what spurred the original thought on this is I have a client that is insisting on a 2 vCPU system with 32 GB's of RAM. To me, with that much RAM the CPU count should be 4 OR with 2 CPU's, the RAM amount should have been lower. 2400 users, the client has not done message profiling for there clients so I'm not entirely sure what the profile is. Started thinking about it, and..well..just ended up going down that path and was curious if anyone had any thoughts about it. Thank you for your time and thoughts, much appreciated. J. If it was helpful, vote for it. If it answered your question, mark it as answered. Small thing to do for free help from a strong community :) There really isn't any significant additional CPU load when you add memory to your system and the sizing calculator is very good. The Exchange team doesn't recommend going over 32GB on a Mailbox server because the additional cost doesn't scale well - performance at 64GB isn't significantly better than at 32GB because of the way the Information Store cache works. So if your client is insisting on 2 CPU and 32GB and are willing to spend the money, then let them. The reason is simply that the additional RAM will allow more effective caching, reducing I/O requirements and allowing for cheaper storage and better overall responsiveness and give them performance to grow into. Anyway, the short answer is that in your scenario running 32GB of RAM won't hurt performance, there are economy issues to consider but you won't see a degradation buy running additional memory.

There's also this - says most of the same things as everyone else: http://technet.microsoft.com/en-us/library/bb738142(EXCHG.80).aspx But note something in the Memory planning section: Cold state operation Cold state is defined as the state of the Mailbox server immediately following a server restart or a restart of the Microsoft Exchange Information Store service. The database cache, which is used to cache read/write operations, is small in size (cold) during this period, so it has a significantly diminished ability to reduce read I/O operations. As the Mailbox server processes messages, the database cache size grows, increasing the effectiveness of the cache and subsequently reducing disk I/O on the server. The more physical memory in the server, the longer it takes the database cache to reach its optimal size. If the storage solution is designed and sized for a server with a large amount of physical RAM (greater than 32 GB), and the disk I/O profile of the users assumes an optimal database cache state (for example, a large, warm cache), the client experience may be compromised due to insufficient disk performance during the cold state periods. Similar to the issue of non-transactional I/O, the storage requirements may be the same for a server with 32 GB of memory as a server with more than 32 GB of RAM. On a properly configured Mailbox server, it should take about 15 minutes to reach the optimal cache state after a cold operation has occurred. Now this is talking about more than 32 GB, and it's a scenario that shouldn't be too common (after restarts) but it's the only thing I could find that talks about a concern when you have too much RAM (other than wasting $$$ as several others have noted in this thread.) And remember to also leave some memory for antivirus, backup and enterprise monitoring products if you need to run those... some of them can be a little bloated.

Completely agree with Neil. I've had designs where the calculated memory requirement in E2K7 was 16GB but the customer's preferred server model in that range had 32GB. There have been no performance issues that I'm aware of. "Neil Frick" wrote in message news:ab0f36e1-bf7b-4092-85fe-8889d16800f1@communitybridge.codeplex .com... Well, what spurred the original thought on this is I have a client that is insisting on a 2 vCPU system with 32 GB's of RAM. To me, with that much RAM the CPU count should be 4 OR with 2 CPU's, the RAM amount should have been lower. 2400 users, the client has not done message profiling for there clients so I'm not entirely sure what the profile is. Started thinking about it, and..well..just ended up going down that path and was curious if anyone had any thoughts about it. Thank you for your time and thoughts, much appreciated. J. If it was helpful, vote for it. If it answered your question, mark it as answered. Small thing to do for free help from a strong community :) There really isn't any significant additional CPU load when you add memory to your system and the sizing calculator is very good. The Exchange team doesn't recommend going over 32GB on a Mailbox server because the additional cost doesn't scale well - performance at 64GB isn't significantly better than at 32GB because of the way the Information Store cache works. So if your client is insisting on 2 CPU and 32GB and are willing to spend the money, then let them. The reason is simply that the additional RAM will allow more effective caching, reducing I/O requirements and allowing for cheaper storage and better overall responsiveness and give them performance to grow into. Anyway, the short answer is that in your scenario running 32GB of RAM won't hurt performance, there are economy issues to consider but you won't see a degradation buy running additional memory. Neil Hobson, Exchange MVP