I've been thinking to buy those G.Skill Ripjaws, they have speed of 3000 MHz but CL16, on the other hand I could take Kingston HyperX /w 2400MHz and CL14, which would be better? Higher speed or lower CL?
Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
What RAM to buy to update new iMac launched today?
- Thread starter spinstorm
- Start date
- Sort by reaction score
Thanks again Onionbobo for doing the research for us. I followed your advice and went with #4 above. I added another 2x8GB chips to go along with the 2x16GB ones I previously purchased. All four chips state CL14 for the HyperX. The computer now runs at DDR4 2400MHz.
Here are the Geekbench scores:
Just checked now, and its up to $283. But based on the pricing history, I don't see the price fluctuations directly related to the new iMac release...
im surprised to see so much difference with just ram. how much of the difference is due to having more ram vs the type of ram?
The results from 0-16-0-16 are the same as 8-16-8-16; therefore, I think it's safe to assume the increase is due to the type of RAM rather than the increase in capacity. For example, the Memory Copy speed (19.1GB/s vs. 12.1GB/s) and Memory Bandwidth (29.9GB/s vs. 22.9GB/s) are much higher with the HyperX RAM vs. factory.
I think it's also reasonable to assume that Apple puts their slower RAM into the base model; the same logic why Porsche/Audi puts different ECU's into certain cars to adjust their performance to meet the price point that car sits at.
where is that compare between 0-16-0-16 and 8-16-8-16? must have missed it.
i doubt apple puts different speed ram in the base vs higher model, they would advertise that to encourage people to take the apple upgrade.
I didn't post the 0-16-0-16 because the numbers are almost identical to 8-16-8-16 for the memory benchmarks.
Just a heads up, you guys. If you are willing to sacrifice the peace of mind of getting brand spanking new, never-been-opened kits of the HyperX Impact 2x16 GB CL 14 2400 MHz SO-DIMMs, Amazon has 2 kits of these marked as "Used -Like New", as in somebody(ies) bought these modules, tried them out, didn't like them or found out they were incompatible with their rigs, and immediately returned them, both at $131.85 a piece (less than half the price of new kits), plus tax and potentially free shipping if you're an Amazon Prime account holder or select super-saver shipping and can wait a few extra days. Get them before they're gone!
https://www.amazon.com/gp/offer-listing/B014R8JWEA/ref=dp_olp_used_mbc?ie=UTF8&condition=used
Edit: These are for the 2x8's as adster below me pointed out, but this site won't let me delete my posts...
https://www.amazon.com/gp/offer-listing/B014R8JWEA/ref=dp_olp_used_mbc?ie=UTF8&condition=used
Edit: These are for the 2x8's as adster below me pointed out, but this site won't let me delete my posts...
Last edited:
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
These are the 2x8's. But thanks for looking out!
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
I purchased the B&H Crucial 32GB kit (2x 16) here when it was $216USD:
https://www.bhphotovideo.com/c/product/1208371-REG/crucial_ct2k16g4sfd824a_32gb_ddr4_2400_mhz.html
No issues whatsoever even though Crucial says it's not compatible on their website.
Final configuration is:
i7 4.2/ 40GB RAM/ 1TB SSD /Radeon 580
https://www.bhphotovideo.com/c/product/1208371-REG/crucial_ct2k16g4sfd824a_32gb_ddr4_2400_mhz.html
No issues whatsoever even though Crucial says it's not compatible on their website.
Final configuration is:
i7 4.2/ 40GB RAM/ 1TB SSD /Radeon 580
14 clocks of 2400MHz is 5.8333... nanoseconds.
16 clocks of 3000MHz is 5.333... nanoseconds.
Thus the CL16 is faster all around. If it were downclocked to 2400, it might be able to run at CL13.
The real question is will the iMac run faster than 2400, or, will it support lower CLs?
I'm having a hard time finding the correct RAM here in Brazil, but this one is available:
https://www.amazon.com/Corsair-Veng...CMSX32GX4M2A2400C16/dp/B01G26166W/ref=sr_1_4?
From what I saw in this thread, it looks like it will work, but I would like a confirmation, since I might not be able to return it. Can someone confirm this will work?
https://www.amazon.com/Corsair-Veng...CMSX32GX4M2A2400C16/dp/B01G26166W/ref=sr_1_4?
From what I saw in this thread, it looks like it will work, but I would like a confirmation, since I might not be able to return it. Can someone confirm this will work?
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
Sorry if I missed it but where is everyone verifying the current active CL in Mac OS?
[doublepost=1497975978][/doublepost]on another note since the system boards in these new machines are obviously reading RAM SPD and setting the speed and latency accordingly I'm wondering what upper limit Apple placed in the controller. Has anyone actually tried RAM faster than 2400?
[doublepost=1497975978][/doublepost]on another note since the system boards in these new machines are obviously reading RAM SPD and setting the speed and latency accordingly I'm wondering what upper limit Apple placed in the controller. Has anyone actually tried RAM faster than 2400?
Since higher tier iMacs come with 2400 MHz ram already, does it make any difference to use the ram people are talking about here as opposed to the ones from macsales or crucial that are listed as compatible?
Good point, I'd love to see a benchmark with even faster ram if possible.
[doublepost=1497981913][/doublepost]
Some of the ram isn't marked as compatible yet, & even more, most people won't gain any benefits from it. I can actually benefit from higher speed ram, but I'm waiting to actually get paid before I order it...& the price is going up unfortunately. For everyone else, it's the "jar of dirt" dilemma. If they want it, then it helps.
Hey all,
So I spoke with a friend who mainly uses windows pc about my options when it comes to buying ram for my 2017 imac with 8gb stock ram. Initially, my plan was to buy 2x16gb to go along with the stock 8gb, for a total of 40gb. Now I've already gone through this entire post, and im pretty certain my question hasn't been asked yet, but apologies if it actually has and i just missed it.
I can see quite a good number of people have gone down this route, whether it be 2x16gb or 2x8gb third party to go with their 2x4gb stock. I know it works. But the question that my friend brought up is that he mentioned he believes ram works better if all the sticks are of the same size. ie 4x8gb, 4x16gb etc. So when I told him my plan to buy 2x16gb to use along with the stock 2x4gb, he said just buy 4x8gb, and get rid of the stock 2x4gb and it'll perform better. Is this true? Does having all same size ram work better? In this case, would i be better off buying 4x8gb for a total of 32gb versus buying 2x16 to combine with stock 2x4gb for total of 40gb.
Thanks
So I spoke with a friend who mainly uses windows pc about my options when it comes to buying ram for my 2017 imac with 8gb stock ram. Initially, my plan was to buy 2x16gb to go along with the stock 8gb, for a total of 40gb. Now I've already gone through this entire post, and im pretty certain my question hasn't been asked yet, but apologies if it actually has and i just missed it.
I can see quite a good number of people have gone down this route, whether it be 2x16gb or 2x8gb third party to go with their 2x4gb stock. I know it works. But the question that my friend brought up is that he mentioned he believes ram works better if all the sticks are of the same size. ie 4x8gb, 4x16gb etc. So when I told him my plan to buy 2x16gb to use along with the stock 2x4gb, he said just buy 4x8gb, and get rid of the stock 2x4gb and it'll perform better. Is this true? Does having all same size ram work better? In this case, would i be better off buying 4x8gb for a total of 32gb versus buying 2x16 to combine with stock 2x4gb for total of 40gb.
Thanks
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
I got my iMac and installed the Crucial memory right away, so I can't say anything about speed but it shows 40Gb of memory @ 2400Mhz
Geekbench score: Single: 5372, Multi: 16223 and memory bandwith: 5604
So far this machine feels very fast comming from a 2010 27" i5 2.8
Geekbench score: Single: 5372, Multi: 16223 and memory bandwith: 5604
So far this machine feels very fast comming from a 2010 27" i5 2.8
As long as the memory pairs are the same size, it will run dual channel and should not reduce performance.
https://www.intel.com/content/www/us/en/support/boards-and-kits/000005657.html
I definitely didn't read this properly before posting my question in #217.
This was the case for you since you bought the HyperX which has faster CL14. If I buy ram that is CL16 or CL17, pairing them with the stock apple ram shouldn't slow it down as you had experienced, correct? Or, is it still better to just run 2x16gb CL16 vs 2x16gb cl16 & 2x4gb cl17?
if pairing up with apple ram, i would recommend going with the closest specs: CL17 2400, single rank if possible.
8GB is probably enough for me. However I bought one 8GB stick of bog-standard Crucial 2400 CL17 non Mac specific RAM (~£58 delivered from Amazon) and installed it in a 4-4-8-0 config. It's all working fine and showing 16GB at 2400. If I need more in the future, which I doubt, I'll just grab another one of the same spec and move everything into a 4-8-4-8 config. Job done...
Just an update for those worried about single and dual rank.
It was noted early on within these forums that Hynix who makes the 8GB RAM many ordered with their iMac’s was single rank but for larger memory sticks Hynix moved to dual rank.
We just weren’t sure what Apple used for the larger memory sticks as they may have used a different manufacturer for 32GB memory for example.
Then Crucial listed their 32GB upgrade kit as single ranked. They even had replies on Amazon advising against purchasing dual rank memory despite that being what OWC was selling for 32GB.
Then for the part Crucial suggested on Amazon as being 2017 iMac ready it was showing dual rank but in the question section they stated it was a typo and will be fixed.
Well I received my Amazon order and it’s this Crucial memory:
http://www.crucial.com/usa/en/imac-(retina-5k,-27-inch,-2017)-imac18,3/CT10559858
And sure enough it’s dual rank. Crucial had updated their site to list it as dual rank whereas it was once listed as single rank.
I returned my unopened Crucial Ballistix ram and passed on others as I was thinking in the long term the diff in rank may be a larger factor (I’ve had ram die on me after several years more than once).
Feeling a little ticked off on how they misrepresented the info.
Plenty others here I’m sure stressed over dual and single rank and possibly passed up better deals due to this as well as all the memory has went up in price since this thread was started.
Edit: To clarify the 32GB memory from both OWC and Crucial are dual rank. In smaller Memory chips like 8GB it’s single rank. This means the ballistic and Kingston memory are identical except for the timings.
It was noted early on within these forums that Hynix who makes the 8GB RAM many ordered with their iMac’s was single rank but for larger memory sticks Hynix moved to dual rank.
We just weren’t sure what Apple used for the larger memory sticks as they may have used a different manufacturer for 32GB memory for example.
Then Crucial listed their 32GB upgrade kit as single ranked. They even had replies on Amazon advising against purchasing dual rank memory despite that being what OWC was selling for 32GB.
Then for the part Crucial suggested on Amazon as being 2017 iMac ready it was showing dual rank but in the question section they stated it was a typo and will be fixed.
Well I received my Amazon order and it’s this Crucial memory:
http://www.crucial.com/usa/en/imac-(retina-5k,-27-inch,-2017)-imac18,3/CT10559858
And sure enough it’s dual rank. Crucial had updated their site to list it as dual rank whereas it was once listed as single rank.
I returned my unopened Crucial Ballistix ram and passed on others as I was thinking in the long term the diff in rank may be a larger factor (I’ve had ram die on me after several years more than once).
Feeling a little ticked off on how they misrepresented the info.
Plenty others here I’m sure stressed over dual and single rank and possibly passed up better deals due to this as well as all the memory has went up in price since this thread was started.
Edit: To clarify the 32GB memory from both OWC and Crucial are dual rank. In smaller Memory chips like 8GB it’s single rank. This means the ballistic and Kingston memory are identical except for the timings.
Let the iMac sleep for a while and then try to revive...did it wake up?
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
this is far from an optimal approach. ram is sold in pairs for a reason, you need well matched ram for it to work well in dual channel. even if you match specs, a future RAM stick will not be a perfect pair. consequences of that can range from a small speed loss to system instability as it forces dual channel.