RAM Overclocking Guide: How (and Why) to Tweak Your Memory

We’ve talked about overclocking processors, and it’s true that optimally tuning a CPU gives you the biggest speed-up, all else being equal. However, slow memory cripples performance, even if your hardware operates at its stock settings. For example, a Haswell-based Core i7 platform paired to slow DDR3-1333 generally fares worse than a comparable Ivy Bridge-based Core i7 backed by superior RAM.

Adata XPG Z1 DDR4 Memory with stylized heat-spreader vs. bare Crucial “Premium” DDR4 MemoryAdata XPG Z1 DDR4 Memory with stylized heat-spreader vs. bare Crucial “Premium” DDR4 Memory

Overcoming slow system memory can be essential to unlocking the potential of your processor, and if you are going for a fast, balanced PC, optimizing your RAM is unavoidable.

We’ve talked about memory timings vs. frequencies and what DRAM is. You've seen us compare the performance of memory ICs and debunk several myths about memory. This article is a more detailed 101-level guide to overclocking RAM, with some pointers and introductions to advanced concepts. We focus on DDR3 and DDR4 DRAM, and leave out the motherboard and processor discussion. We are using the words “RAM,” “memory,” and “DRAM” interchangeably throughout the article. The technical term “IC” (Integrated Circuit) and the slang “memory chip” both refer to pieces of silicon soldered onto the memory circuit board to create a dual in-line memory module (DIMM).

There are some scenarios where tinkering with a memory module's parameters, include clock rate and voltage, is almost required. First, if you purchase high-end RAM, its default boot settings may not be the values advertised. Vendors sometimes set starting values to something they know will POST in a plethora of system configurations—and it’s up to you to raise its performance. Second, if you’re overclocking your processor by increasing its base clock (BCLK), your RAM gets overclocked automatically, and you may have to change the memory’s frequency and timings for better/more stable performance.

Two Crucial 8GB DDR4 ICs in packagingTwo Crucial 8GB DDR4 ICs in packaging

If neither scenario is true, you may still want to overclock your RAM. Systems with APUs often benefit immensely from better memory performance, since APUs use system RAM like discrete graphics cards use VRAM. Gaming on a processor with a built-in graphics engine is much faster when you complement it with the fastest memory subsystem possible. Tasks that involve large arrays, such as scientific computing, running virtual machines, databases, graphic design programs, and caching are all prime candidates for overclocked memory. Even gaming systems with discrete graphics benefit in popular titles like GTA V.

Finally, overclocking RAM is one of the cheapest and most effortless ways to squeeze performance out of a system. It usually doesn’t require additional cooling, especially if you're only shooting for a modest boost, and you won't be forced to shop for a beefier PSU since RAM accounts for a very small part of your power budget.

So why wouldn’t you want to overclock your memory? Perhaps your processor's integrated memory controller (IMC) can't go any faster or handle additional voltage. Or maybe power consumption is an issue. Otherwise, we don’t see a reason not give it a try; the previously-mentioned vendor default values programmed into the EEPROM of the memory chip mean that the system should always POST and boot properly before the user-set values cut in, so it’s hard to mess anything up on the first few passes.

There are three main ways to begin overclocking memory: increasing the platform's BCLK, directly commanding an increase in the memory’s clock rate (multiplier), and changing the timing/latency parameters. Any of these changes may require increasing the voltage (VCCSA and VCCIO, otherwise known as VTT, as well as the DDR voltage to the memory chip itself) to maintain stability. As it was for overclocking a processor, the values you'll manipulate are interdependent, and need to be adjusted iteratively. We’ll go into each of them in further detail, provide some further guidance on hardware selection, and navigate some of the software tools available to you.

MORE: Best Memory

MORE: DDR DRAM FAQs And Troubleshooting Guide

MORE: The Most Common DDR DRAM Myths Debunked

MORE: Navigating the Memory Upgrade Jungle

MORE: All Memory Content

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  • Sakkura
    Perfect timing, I was just about to get to work on my DDR3-1600 kit. Gotta squeeze out all the performance possible from my aging Ivy Bridge build. Especially now that I'm running VR.
  • Amdlova
    No i don't want oc the memory if i can't oc the ssd :)
  • BobsKnob
    You know why there's no benchmarks? Because overclocking memory offers such small 'real world' gains that it's not even worth it. You might as well try to overclock your usb ports. This is just a lame attempt to advertise products, in this case Kingston and Arctic heat spreaders and try to pass it off as reporting.
  • derekullo
    They also mentioned Mushkin, Crucial and G.Skill.

    Heaven forbid they mention the manufacturer of the ram in an article about overclocking ram.

    Now if this would have been an article about Farcry 5 or Elder Scrolls 6 and they had a picture of an Arctic Heat Spreader then you would have been on to something.
  • BobsKnob
    Thank you for proving my point. It's just advertising masquerading as reporting.

    You know, there used to be a time when Tom's did real, unbiased reviews and reporting. When something sucked...it sucked and the review wasn't candy coated.
  • damric
    Well done. Will there be a Part 2 that dares to tweak secondary timings and beyond?
  • dish_moose
    I'm with Bob on this one - until you show real wold benchmarks showing real improvement from OC RAM, I won't waste my time.
    -Bruce
  • Maxxtraxx
    Check out the youtube channel Digital Foundry, this video specifically: https://www.youtube.com/watch?v=Er_Fuz54U0Y
  • Maxxtraxx
    Proof of increased performance from Ram Overclocking from real world benchmarks can be found here:
    https://www.youtube.com/watch?v=Er_Fuz54U0Y

    Am I not allowed to edit my own posts? or am i really missing something here? I wanted to say more after I posted but could not find any way to edit my own post.
  • BobsKnob
    What GPU is being used for that test?
  • BobsKnob
    Also, when I skip through that video, I see a lot of the FPS's are similar regardless of ram speed.
  • Maxxtraxx
    Watch the whole GTA5 section of the video, also here is a second video from DF on the same subject:

    https://www.youtube.com/watch?v=qksXthUcbiQ

    You'll see the same FPS results there the gains are anywhere from a few FPS more under light CPU loads to 20FPS more with heavier loads.

    The amount of FPS gained by RAM overclocking is much less consistent when compared to GPU overclocking due to it being bound to the CPU job of keeping the GPU fully fed without bottle-necking.

    The CPU can go from doing very little to supply the GPU to doing a great deal at different times during the game. The GPU, unless it hits a frame limiter like v-sync will be running at 100% all the time unless it is bottle-necked by the CPU.
  • blackmagnum
    Did you know that overclocking the memory might corrupt the data? That's why you should only overclock ECC memory.
  • inmyrav
    How about some measurements to show the alleged benefits of overclocking memory? I have never seen a significant impact on gaming performance even from significant overclocks / reduced timings in memory. I'd be interested to see how much the benefits are and where exactly they exist, if they do?
  • Sabishii Hito
    Memory OC is mainly for fun and competitions, and I thoroughly enjoy it.
  • daglesj
    Buy the ram that looks the coolest in your motherboard. That's the only valid advice you need these days.
  • g-unit1111
    That's very interesting. I had no idea you could identify that much from a RAM module. Kind of like how you can identify everything about a car from the VIN number.
  • JackNaylorPE
    Quote:
    But current-generation heat spreaders from reputable vendors do make a difference in operating temperatures, and when the same kit is provided in two different packages—one with a heat spreader and one without—going for the heat spreader makes technical sense.


    What is the difference ? Why is it significant ? Here I see the aesthetics as the primary driver here. Yes, of course, two sets of modules, one with and one w/o the HS, take the one with ... but what is the thermal issue here ?. I have not heard of an issue with RAM temps since DDR2. As an analogy, while I saw the reasoning behind putting a hybrid cooler on a FuryX, what is the point on a AIB GTX 1070 ? The card operates well below (10C) it's throttling point on air so, exactly, what is the hybrid doing for me ? What do I get out of the extra $100 ?

    The only cooling effect of these big tall toothy coolers is that they "look cool". While they served a purpose (when they were effective) w/ DDR2, they were absolutely useless on DDR3. And DDR4 runs even cooler.

    http://benchmarkreviews.com/index.php?option=com_content&task=view&id=773&Itemid=67&limit=1&limitstart=1
    Quote:
    At more than 2" tall in certain areas the Corsair Vengeance could pose a problem for users like me who use large coolers such as the Scythe Mugen 2. I was able to use the Corsair Vengeance only after I mounted the fan on my cooler on the backside. Size is definitely a concern with heat spreaders of this size and therefore I encourage users to check that they will have enough space under their heatsinks before purchasing the Corsair Vengeance kit.


    http://benchmarkreviews.com/index.php?option=com_content&task=view&id=773&Itemid=67&limit=1&limitstart=6
    Quote:
    The problem I have with the Corsair Vengeance is the same I have with many kits of RAM on the market. Companies insist on putting large coolers on their RAM and it limits the choice in CPU heatsinks that can be used within users system. DDR3 does not require these elaborate coolers with its lower voltages which translate to lower temperatures then RAM saw during the DDR, and DDR2 era. Corsair is correcting this with low profile versions of its Vengeance line but ultimately I would like to see the average size of coolers drop instead of having to look for specific low profile versions of a memory line.


    When such a "makes a difference" statement is made, as a reader, I want to see the data behind the conclusion.. 1) what are the differences in temps ? 2) how is this significant ? and 3) what are the performance impacts in something we actually do (besides benchmarks).

    With regard to the "glued on" comment, this is an issue that we never see mentioned in reviews / comparisons. Some RAM HSs can be removed with a screw ... some are glued on, why not mention this in a comparison review ? GFX card reviews typically include, RAM manufacturer, specs, how it is being cooled and yet this is rarely done for system RAM.

    Would love to see time and effort put in to showing more than "same ole same ole".

    For example, gaming average fps is limited primarily by the GFX card performance... tho there is some general acceptance that CPU can be limiting in certain games, especially when in multi-player mode. What is less accepted is that memory speed can affect performance... and when this subject is argued, we oft see links to tests that "prove" the hypothesis via "google something that shows this". Sometimes that results in a link that can prove both opposing arguments

    http://www.tomshardware.com/reviews/32-gb-ddr3-ram,3790-10.html

    Metro 2033 shows no performance gain going from 1600 to 2400 DDR speed, and yet F1 shows an 11% increase in average fps. Like anything else, system performance is impacted by the weakest link in the chain. If RAM is not the weakest link, then the impact is zero. So a "test" that "proves this" is misleading. To make testing useful, the script should involve determining under what circumstances RAM becomes the bottleneck and then seeing if faster RAM or overclocking can have in impact.

    Among the areas of relevance therefore, based upon past articles on the topic.

    -what games / programs can be impacted ? (CAD, video editing ...)
    -what actions within those games / programs can be impacted ?
    -what parameters need to be analyzed ... for example min fps vs avg fps ?
    -Is the test bed adequate to perform the evaluation ... for example, what happens to previous tests when 2nd GFX card is added ? ... 3rd and 4th

    Was never a popular undertaking, my guess cause of the amount of effort involved, but here's some old links which did look into some of these aspects

    http://www.anandtech.com/show/2792/12

    22.3 % (SLI) increase in minimum frame rates w/ C6 instead of C8 in Far Cry 2
    18% (single card) / 5% (SLI) increase in minimum frame rates w/ C6 instead of C8 in Dawn of War
    15% (single card) / 5% (SLI) increase in minimum frame rates w/ C6 instead of C8 in World in Conflict

    Also see http://www.bit-tech.net/hardware/memory/2011/01/11/the-best-memory-for-sandy-bridge/1

    http://www.anandtech.com/show/7364/memory-scaling-on-haswell/10
    http://www.anandtech.com/show/6372/memory-performance-16gb-ddr31333-to-ddr32400-on-ivy-bridge-igp-with-gskill/14
  • gamebrigada
    You should mention that some games do not like memory overclocks. Ubisoft is pretty famous in this regard some of their games will run very low frame rates with any overclock no matter how stable. FarCry 4 is a good example.
  • RedJaron
    Everyone asking for benchmarks showing the benefits of OC'd RAM, look back at any number of SBMs, particularly any Codemasters racing games. You will see big fps gains when RAM bandwidth is increased. Other games, hardly anything. This is nothing new. Most games don't care about CPU OCing either.

    However, games aren't the only thing computers are used for. Many professional apps, particularly Adobe products like Premiere and After Effects, are very RAM sensitive.

    Anonymous said:
    You should mention that some games do not like memory overclocks. Ubisoft is pretty famous in this regard some of their games will run very low frame rates with any overclock no matter how stable. FarCry 4 is a good example.
    I'd love to see the proof of this. It's not difficult to OC your RAM poorly, resulting in lower performance all around, not just in one game. My suspicion if that is the case you saw here, if indeed you did see it and aren't simply repeating something told you.