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Some mainboard producers add a + to the specification of supported memory types (e.g. for ASRock X99 Extreme 3 supports DDR4-3000+). Does DDR4-3000+ somehow differ from DDR4-3000? The wikipedia article on DDR-SDRAM doesn't contain the sign+ or mention anything related. I don't see the difference reflected in selection filters in online stores.
Karl Richter
Posted 2015-02-14T13:12:59.630
Reputation: 1 641
16
The "+" usually indicates that the motherboard supports RAM with a frequency of over 3000MHz. The OC in brackets means that the motherboard allows the RAM to be overclocked. The caveats being that you may need to increase the voltage and/or the timings in order to accommodate the higher frequency.
This article provides a good explanation on memory timings (e.g. 9-9-9-24):
Yass
Posted 2015-02-14T13:12:59.630
Reputation: 3 276
1"The caveats being that a higher overclock/frequency will result in an increase in voltage and latency (in most cases)."
The latency is measured in cycles(not time) for SDRAM, so the actual latency depends on latency number / the frequency you can reach. – rsaxvc – 2015-02-14T21:06:55.547
I didn't say it's measured in time. I simply stated that a greater overclock will have an adverse effect on latency. – Yass – 2015-02-15T01:38:27.617
That's just it, overclocking means you may need more latency cycles, but not actually more latency. 2 cycles at 100MHz is the same latency as 3 cycles at 150MHz. If you can run at 125MHz with only 2 latency cycles, the latency has decreased rather than increased.
(Everything else in your answer I agree with and was helpful) – rsaxvc – 2015-02-15T18:33:13.140
So, are you saying I should change my answer to say latency cycles, instead of just latency? – Yass – 2015-02-15T19:24:08.330
1I would just mention that you'll likely need to adjust the timings and/or voltages along with the new speeds. – rsaxvc – 2015-02-15T23:58:06.253
Okay, I think that's fair. – Yass – 2015-02-16T07:07:35.857