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DRAM-Feature

Welcome to ExtremeTech'south comprehensive RAM guide, in which nosotros'll respond a broad range of questions related to how much system RAM you need these days, whether or non information technology's worth it to upgrade older systems, and whether DDR3 or DDR4 (the new chief types of system RAM) is a meliorate investment option.

Information technology'due south interesting to look back and see how much things accept changed over the past twenty years. People have been writing RAM guides for decades, but back when I was learning about calculating, much more accent was paid to the specific technical implementation of any given RAM standard.  Fast Page Mode RAM, EDO RAM, SDRAM, DDR, and RDRAM are but a few of the standards that existed elbow-to-elbow, and which type of memory your system used often determined if it was worth upgrading.

Present, things are simpler. While a few of you may nonetheless take DDR2-based equipment from 2005 to 2009, the majority of systems today are likely using DDR3. That's the memory standard we'll focus on; if you have DDR2-related questions you're welcome to drop them in the comments.

How much RAM do you need?

How much RAM y'all need in a arrangement depends on what you intend to do with it, how long you intend to keep it, and whether or not you lot can upgrade your retentivity mail-buy. This final bespeak is important, as many high-end laptops have eliminated user-upgradeable RAM in order to reduce arrangement thickness by roughly six nanometers.

Adding additional RAM to any laptop generally increases ability consumption by a measurable (if small) corporeality, but this shouldn't exist an issue for nearly users. It's also better to have a scrap as well much RAM than too little, as whatever you gain in power savings yous'll promptly lose to increased disk paging.

Apple'south MacBook Air offers 4GB of RAM, but most of the systems from Dell, HP, and other OEMs get-go at 8GB, and I remember that's the better sweet spot. That's not to say you lot tin't get by on 4GB — you admittedly tin — merely 8GB gives yous a bit more breathing room.

MacBook Air

The MacBook Air ushered in the era of soldered DRAM. Anybody followed.

There's at least some evidence that modernistic desktop applications have slowed the rate at which they need more RAM. From 1990 to 2000, Photoshop's minimum RAM requirement rose from 2MB to 64MB, a 32x increase in 10 years. It took another sixteen years to match this early rate (from 64MB in 2000 to 2GB in 2022).

A lightweight system today can get by with 4GB of RAM. 8GB should be plenty for current and well-nigh-term time to come applications, 16GB gives you comfortable infinite for the future, and anything over 16GB is likely overkill unless you specifically know you lot demand it (such as for video editing or audio post-production). This holds true for desktops as well as laptops.

DDR3 or DDR4?

Right now there's plenty of DDR3 systems still being sold, merely DDR4 has already begun to supplant it on the mass market. If you're building a new system and don't accept a specific reason to use DDR3, we'd recommend buying hardware that's compatible with DDR4.

With that said, if your system does use DDR3, that'south non the problem that it used to be. In the erstwhile days, a computer stuck on, say, PC133 SDRAM was at an intrinsic performance disadvantage compared with systems that used DDR, particularly at college clock speeds. That's less true than information technology used to be, and it may make sense to upgrade a DDR3 system depending on what you have and when you bought information technology. The reason to use DDR4 at this point has more to do with long-term retention pricing trends and hereafter compatibility than key functioning. We'll explore current price and the performance question later in this guide.

Does faster RAM heave organization operation?

Curt answer: Sometimes, just not past much.
Medium answer: It depends on other organisation components, workload, and whether or non y'all're using integrated graphics.

Longer answer: Run across below.

RAM operation is controlled by two metrics: Clock speed and access latency. Access latencies tend to fall much more slowly than clock rates — as this diagram shows, the memory cell wheel time of PC100 is roughly equivalent to DDR4-2133. DDR4 doesn't match DDR3-2133 wheel times until you hit DDR4-4266.

RAM cycle times at various clock speeds

RAM bike times at diverse clock speeds

Conventional wisdom is that RAM latency has get relatively less important in recent years, cheers to a combination of factors. Back when L2 caches were modest, retentiveness controllers were off-dice (and clocked at a fraction of CPU speed), and there were no L3 caches, retention latency had a larger bear on on overall organisation performance. Modern CPUs are typically backed by 512 to 1MB of L2 (per core), and ane.5MB to 2MB of L3 enshroud (per cadre). Retention controllers are now integrated on-die and run at total processor speed. As a consequence, RAM latency simply doesn't play equally large a part as information technology in one case did in determining performance.

Every bit for raw memory bandwidth, the aforementioned large caches that minimize the bear on of RAM latency in most applications also limit the impact of retentiveness bandwidth. Desktop applications are, for the most part, latency-sensitive, not bandwidth-sensitive.

These performance results are from Corsair, but they match extensive testing on the topic. AMD APUs love fast DRAM.

These operation results are from Corsair, merely they match all-encompassing testing on the topic. AMD APUs dear fast DRAM.

There's one major exception to this rule: Integrated graphics performance. Both Intel and AMD integrated graphics meet some benefit from college-speed retention, simply the gains are specially large on the AMD side. This has proven true for every APU since at least Trinity, and will probable continue to exist accurate for DDR4-based hardware. The advent of HBM2 in APUs will finally throw open the bandwidth floodgates — until then, integrated graphics will e'er be somewhat bandwidth-limited.

What about high-finish gaming performance?

Until recently, I would've told you that high-speed RAM had very niggling impact on high-end gaming. A recent study from Digital Foundry, however, appeared to show otherwise.

Digital Foundry'due south total review is worth a read — they tested a Core i5-6500K with a GTX Titan X at 1080p in a diversity of titles to measure out both the affect of overclocking DDR4 and of higher clock speeds. What nosotros've washed beneath is map the gains they saw from overclocking DDR4 from 2133MHz to either 3066MHz or 3200MHz. These 2 clock speeds always delivered the best performance, but some titles showed the greatest gains at 3066MHz and regressed at 3.2GHz, while others showed continual comeback.

GameScaling

This dataset is limited, but information technology does point to some full general trends. Offset, minimum frame rates tend to increase more boilerplate frame rate. Second, the gains are championship-specific: Battleground four, Crysis 3, and COD Advanced Warfare all see gains under 10%, while GTA 5, Far Cry four, and The Witcher iii are all at or in a higher place the 15% mark. Assassin's Creed Unity splits the difference, with a 15% bound in minimum frame rates and a 6% rise in boilerplate frame rates.

The Digital Foundry team claims to encounter a similar set of results when using faster DDR3 in Fallout 4 and a GTX 970. As this screenshot shows, FO4's minimum frame rate rises dramatically when paired with DDR3-2400 instead of DDR3-1600.

Fallout 4 RAM scaling

Image by Digital Foundry

Over again, however, a caveat is in guild. Gamebryo games have always tended to be very friendly to more memory bandwidth — much more than and then than yous would otherwise expect. We've seen this in Skyrim, and we're seeing it, apparently, in Fallout four likewise. TechSpot has more on this, and their data shows that Intel fries gain more AMD does from faster DDR3. This actually makes sense — the FX-8350'south L3 and integrated retentiveness controller are clocked at 2.2GHz, and the FX-8350 has other latency issues that will blunt the impact of faster RAM.

The not-Fallout four gains aren't huge, considering that nosotros're increasing RAM clock by 50%, but these results fly in the confront of previous testing. For years, conventional wisdom has been that RAM clock speed is most irrelevant to game performance, provided that yous've met the minimum threshold for a title.

Information technology'south possible that we're seeing the touch of new game engines or that the GTX Titan X that Digital Foundry used was powerful enough to bear witness an impact, whereas previous video cards were non. The pick of resolution (1080p) and potentially even the use of FCAT over FRAPS could also take played a part.

One major signal to exist aware of if y'all intend to try and run extremely high memory clocks: If you're ownership a bunch of DDR3-1600 (or DDR4-2133) to stick in a box, you probably don't demand to worry about sticking to the "manufacturer recommended" section of your motherboard manual. If, on the other mitt, you desire to run maximum clock speeds, take the time to review precisely which RAM your motherboard vendor recommends yous use. Proceed in mind that running high RAM clocks is oftentimes at odds with running big amounts of retentivity. Single-sided DIMMs tend to tolerate high frequencies and low latencies ameliorate than double-sided retentiveness, and you lot ideally don't want to use more than than one DIMM per channel unless your motherboard vendor specifically recommends differently.

Skip this step, and you may well stop upward with memory that tin can't reach its full potential in your system.

Next, nosotros'll cover upgrading and cost. What clock speeds make sense, and which don't?

Earlier we discuss the upgrade question, allow'southward have a expect at what you can wait to pay for DDR3 and DDR4 today. We compared the price of 16GB of DDR3 and DDR4 memory throughout their respective clock frequencies, using Newegg.com as our source.

DDR3-Scaling

DDR3 scaling. Toll of 16GB

DDR3 prices are fairly stable until y'all attain DDR3-2666. DDR3-2400 may be worth the extra dollars, since y'all're paying 18% more and receiving a fifty% clock boost, simply nothing above 2.4GHz is worth your greenbacks.

The rapid price increases higher up 2.4GHz don't just reflect enthusiast price gouging, only the difficulty of getting adept yield on DDR3 memory at these frequencies. DDR3 wasn't designed to calibration to such high clock rates, and the 2666MHz price reflects that.

DDR4-Scaling

DDR4 shows a more leisurely curve. There's no single inflection betoken at which toll skyrockets. $105 for 16GB of DDR4-3200 isn't a bad deal if yous can spare the cash — and if you tin can't, 16GB of DDR4-2133 isn't going to get out you gasping in the latest games.

Should you upgrade older systems?

Upgrades are another expanse that deserve consideration. There are plenty of offset-generation Core i7 systems that likely opted for DDR3-1066. If y'all've got a Core i7 rig from this era with 4GB to 6GB of relatively low-speed DDR3, is it worth upgrading to loftier-speed RAM?

The reply here is probably, but I wouldn't go overboard. 12GB of DDR3-1600, for case, is around $60 at Newegg. College frequency kits aren't always offered in the multiples of 3 that the old X58 motherboards liked best, but if yous can find a DDR3-1866 kit that matches your lath and doesn't cost much more, I'd say get for it.

There are, however, some caveats to this position. AMD'due south Phenom II and commencement-generation Intel Core i7 products (Nehalem microarchitecture, codenamed Bloomfield or Lynnfield) all used "uncore" clock speeds well below the CPU clock. The Phenom II'due south L3 cache and integrated memory controller were clocked at 2GHz, while the Cadre i7 920 and 940 were clocked at 2.13GHz. This will limit the benefit you see from faster DDR3 unless yous also overclock the uncore; clocking retention faster than the memory controller rarely results in improved functioning.

AMD Bulldozer and Piledriver CPUs both use uncore clocks effectually two.2GHz, as do the visitor's APUs. Intel switched to an uncore clocked at base CPU frequency with Sandy Bridge, which typically means 3GHz or more.

DDR3-2133 should be considered the highest-end "applied" upgrade clock for older hardware. If you've already got eight-16GB of DDR3-1600 I wouldn't bother, but if y'all opted for DDR3-800 to DDR3-1066 when yous built your system and have merely iv-6GB of retentivity in it, you may see some modest improvements for relatively little cost. Be brash, nonetheless, that a faster GPU will normally be the better system upgrade if y'all have to pick between RAM and graphics, and can't afford to practise both.

Putting it all together

We've touched on a groovy many topics in this story, and then I'll summarize the findings here. If you're planning to buy a new laptop, check to see if it allows for RAM upgrades or not. This isn't a given anymore. Mobile users with lite employ cases tin go past on 4GB of RAM; 8GB is a skilful target for the majority of people. If you're a gamer, photograph/video editor, or planning to do CAD/CAM work, we recommend at least 16GB of memory. Chances are if you lot need more than than that, you already know it.

If you're a desktop user with an older organisation, especially an older enthusiast rig, adding faster RAM may help you eke a few more years out of your hardware, especially if you lot merely accept 6GB of RAM today.

Gamers looking to build new desktops should target DDR4 and a 16GB sweet spot. Higher frequency DDR4 is better than lower, all else being equal, just don't worry about your rig beingness crippled if you need to shave a few dollars off the cost. DDR4 volition exist on the marketplace for years to come and the prices volition inevitably come up down further. This is particularly true if yous're going to build with a midrange GPU; a GPU-limited game won't see a huge functioning shift from using faster DDR4.

If you want to install massive amounts of retentivity now, there's aught wrong with jumping for 32GB of DDR4, but I don't expect information technology to exist of much practical benefit for the overwhelming majority of people. Most applications take their memory consumption cues from Microsoft, and Microsoft has held the bar steady on Windows for a very long fourth dimension. If you lot're planning to edit 5K videos or RAW 4K photographic camera footage this obviously doesn't apply to you — stuff as much RAM in your chassis as you similar in that example.

Hopefully this helps clear upwards questions, but if you lot've got an issue I haven't touched on, sound off in the comments beneath.

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