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1333MHz vs 1600MHz RAM?

LarryJoe33 said:
One last question for you. My MBP has an i5
(2.4 GHz Intel Core i5)
and yours has an i7, do you think this will be an issue? I tried scouring geekbench for an i5 setup like mine and haven't found anyone running at 2133 with an i5. Lots of i7's. I guess I will know soon enough. RAM coming Monday.
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Oh, that could really be a problem, but not because of the i5.

It seems (I am not 100% sure) the native speed of that RAM is 1.600 MHz (PC3-12800).

My iMac only recognized them as 1.333 MHz and both, that iMac's i5-2400 and your's, what has to be the 13" with an i5-2435M only support up to 1.333 MHz (PC3-10600) :(, same for the i7 in the 13" but my i7-2860QM does support 1.600 MHz RAM.

Here is a comparison for the CPUs: http://ark.intel.com/compare/52207,60636,53476


And here a screenshot of all CPUs that were available in the Late 2011 MBPs:

Screen Shot 2017-08-26 at 9.15.40 PM.png


Source: http://www.everymac.com/systems/by_year/macs-released-in-2011.html
 
Erdbeertorte said:
Oh, that could really be a problem, but not because of the i5.

It seems (I am not 100% sure) the native speed of that RAM is 1.600 MHz (PC3-12800).

My iMac only recognized them as 1.333 MHz and both, that iMac's i5-2400 and your's, what has to be the 13" with an i5-2435M only support up to 1.333 MHz (PC3-10600) :(, same for the i7 in the 13" but my i7-2860QM does support 1.600 MHz RAM.

Here is a comparison for the CPUs: http://ark.intel.com/compare/52207,60636,53476


And here a screenshot of all CPUs that were available in the Late 2011 MBPs:

View attachment 714652

Source: http://www.everymac.com/systems/by_year/macs-released-in-2011.html
Click to expand...
Ugh, what's your confidence level it will clock over 1.333 Mhz? I at least expected 1.600 Mhz. Thanks for the comparison. I understand the similarities between your iMac 2400 and my 2435 only supporting 1066/1333, but your i7 only supports 1066/1333/1600 yet runs at 2133? Maybe there is some hope?

I actually bought two kits ,one off Kingston and one from Amazon. I got impatient after I got the shipping time from Kingston (next Friday) so I bought another from Amazon prime and it gets here Monday. Looks like I may have a lot of returning to do.
 
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Based on my experience with Intel processors, clock multipliers, and chipset, it's unlikely the ram will run at a fsb speed in excess of 1333.

The cpu multiplier is locked and increasing the fsb over 1333 will cause the processor to overclock too. To increase fsb without increasing cpu speed, the chipset needs to support asynchronous settings between fsb and processor speed or have a CPU with an unlocked multiplier like the k-series of Intel processors.

http://ark.intel.com/products/60636/Intel-Core-i5-2435M-Processor-3M-Cache-up-to-3_00-GHz
 
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Audit13 said:
Based on my experience with Intel processors, clock multipliers, and chipset, it's unlikely the ram will run at a fsb speed in excess of 1333.

The cpu multiplier is locked and increasing the fsb over 1333 will cause the processor to overclock too. To increase fsb without increasing cpu speed, the chipset needs to support asynchronous settings between fsb and processor speed or have a CPU with an unlocked multiplier like the k-series of Intel processors.

http://ark.intel.com/products/60636/Intel-Core-i5-2435M-Processor-3M-Cache-up-to-3_00-GHz
Click to expand...

It seems a stretch for sure but how do you explain Erdbeertorte i7 running at 2133?

http://ark.intel.com/products/53476/Intel-Core-i7-2860QM-Processor-8M-Cache-up-to-3_60-GHz

Also, keep in mind that this particular RAM "self overclocks":

http://www.hyperxgaming.com/US/memo...al (Kit) Capacity=16GB&Kit=Kit of 2#v-overlay

Impact DDR3.png
 
The Kingston ram will support the maximum speed supported by the motherboard BIOS as per this disclaimer:

HyperX PnP memory will run in most DDR3 systems up to the speed allowed by the manufacturer's system BIOS. PnP cannot increase the system memory speed faster than is allowed by the manufacturer's BIOS.

I take this to mean that the ram will limit itself to the fastest speed supported by the chipset. If a late 2015 iMac supports a maximum frequency of 1867, the ram will not run above 1867. Ram modules use serial presence detect (SPD: https://en.m.wikipedia.org/wiki/Serial_presence_detect) to match its settings, such as frequency and latency, to the computer bios. I don't see apple allowing anyone to access a computer bios to manually overclock the fsb or running the cpu "out-of-spec".

As I mentioned in an earlier post, I would like to find a way to confirm that 1600 ram in an early or late 2011 13" Macbook pro is running the fsb at 1600 when Intel listed 1333 as the maximum ram speed supported by the i5-2435 processor. I have an early 2011 13" Macbook pro with 2x4 Gb 1600 ram that is recognised as 1600 Mhz ram in the "about" screen.

Edit: forgot to mention that this Kingston ram probably has very low latency at 1300, 1600, and 1867 which could explain the better benchmark scores over ram that is rated to run at 1333, 1600, or 1867 with higher latencies.
 
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Audit13 said:
The Kingston ram will support the maximum speed supported by the motherboard BIOS as per this disclaimer:

HyperX PnP memory will run in most DDR3 systems up to the speed allowed by the manufacturer's system BIOS. PnP cannot increase the system memory speed faster than is allowed by the manufacturer's BIOS.

I take this to mean that the ram will limit itself to the fastest speed supported by the chipset. If a late 2015 iMac supports a maximum frequency of 1867, the ram will not run above 1867. Ram modules use serial presence detect (SPD: https://en.m.wikipedia.org/wiki/Serial_presence_detect) to match its settings, such as frequency and latency, to the computer bios. I don't see apple allowing anyone to access a computer bios to manually overclock the fsb or running the cpu "out-of-spec".

As I mentioned in an earlier post, I would like to find a way to confirm that 1600 ram in an early or late 2011 13" Macbook pro is running the fsb at 1600 when Intel listed 1333 as the maximum ram speed supported by the i5-2435 processor. I have an early 2011 13" Macbook pro with 2x4 Gb 1600 ram that is recognised as 1600 Mhz ram in the "about" screen.
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Thanks, interesting, by the way, I am a former overclocker from my Windows/Gaming days. Asus Motherboard's, unlocked CPU's, multipliers, etc. I am a little rusty, but I am following you.

That said, there does seem to be an anomaly where you have the i5-2435 "running" ram at 1600, or maybe just showing but running at 1333? Although why would it read as 1600 when the chipset doesn't support it?? Same for the i7 running at 2133.

Well, I guess I will know my answer Monday. If you are correct, it should visibly down clock to 1333 (native is 1600 I believe). But why doesn't yours down clock (visibly in About) to 1333?
 
The os is probably picking up the ram frequency from the interaction of the bios and ram spd settings. The ram speed shown in the system report may not be the frequency at which the memory bus is operating, only the speed at which the ram is capable of operating.
 
I don't know. I completely follow your logic, but I am not sure I buy the reported theory. From my experience, the reported system stats are what they are. Did you see Erdbeertorte's geekbench test results earlier in this thread?

Again, we shall see. This is a very expensive test! Thank god for Amazon Prime hassle free returns and hopefully Kingston will be the same way. Actually, hopefully I am only returning one set.
 
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I understand your scepticism but running the fsb at 1600 with a locked cpu multiplier would overclock the cpu by quite a bit unless the cpu clock is not dependent on fsb. I also doubt that these Macbooks wouldn't use an Intel chipset but I'm really not 100% sure.

I think I'll try some benchmarks to see what happens.

I'm very curious to see your results. Good luck, I'm rooting for you!
 
Audit13 said:
I understand your scepticism but running the fsb at 1600 with a locked cpu multiplier would overclock the cpu by quite a bit unless the cpu clock is not dependent on fsb. I also doubt that these Macbooks wouldn't use an Intel chipset but I'm really not 100% sure.

I think I'll try some benchmarks to see what happens.

I'm very curious to see your results. Good luck, I'm rooting for you!
Click to expand...
Thanks! Should be fun.
 
I ran geekbench with 1333 (https://browser.geekbench.com/v4/cpu/3814261) and 1600 (https://browser.geekbench.com/v4/cpu/3814348).

The scores went up with the 1600 ram as I expected but I can't figure out what the ram timings are under each scenario.

Edit: did some more research and it looks like the 2nd generation Intel CPUs and chipsets are capable of running the memory and cpu clock asynchronously which is good news. I ran geekbench on a late 2013 13" rMBP: https://browser.geekbench.com/v4/cpu/3814511

Based on the memory scores, it looks like the ddr3 1600 on my early 2011 13" MBP is running at 1600 speeds.
 
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Nice, this is indeed encouraging. Thanks for doing this. So, we have the same i5 2435 with a spec of 1066/1333 that is showing and running at 1600. This is encouraging as Erdbeertorte put the Hyperx RAM in an i5-2400 and it ran at 1333, glad to know the i5-2435 is capable of going over spec (based your tests). Looks like I need to do a geekbench test right now with my 16GB/1333 Crucial Ram.

Fingers crossed.
[doublepost=1503800916][/doublepost]https://browser.geekbench.com/v4/cpu/3815258
 
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Here is a new Benchmark with Sierra and Geekbench 4 for more recent comparisons. Scores are calculated differently compared to GB3 and always show a lower value.

https://browser.geekbench.com/v4/cpu/3822874

Comparison to the slower RAM may follow later if I find them.

Edit: @LarryJoe33 Have a look at the memory copy/latency/bandwidth in your benchmark compared to mine.


Screen Shot 2017-08-27 at 23.48.56.png

Screen Shot 2017-08-27 at 23.49.02.png
 
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Erdbeertorte said:
Edit: @LarryJoe33 Have a look at the memory copy/latency/bandwidth in your benchmark compared to mine.
Click to expand...

Thanks, I just did and your single core Memory BM is much higher. Is this what you are referring to? What are your observations/comments? I am not memory bandwidth expert (although I am getting there!). Also, I ran another geekbench. Yesterday's was with a crap load of stuff running including a TM backup. Here is mine with nothing running:

https://browser.geekbench.com/v4/cpu/3818783

EDIT: I see what you mean now! Under memory bandwidth. That's crazy throughput.
 
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Day two with this overclocked HyperX RAM. So far, nothing but increased response time. Completely stable (again, day two). If you are thinking about adding RAM to your older MBP, the HyperX self overclocking RAM is about $30 more than reputable brand name DDR3 at 1333 and worth it.
 
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