LET’S TALK ABOUT…HOW MUCH RAM DO YOU NEED
How much RAM
you need in a system depends on what you intend to do with it, how long you
intend to keep it, and whether or not you can upgrade your memory
post-purchase.
Adding
additional RAM to any laptop generally increases power consumption by a
measurable (if small) amount, but this shouldn’t be an issue for most users. It’s also better to have a bit too much RAM
than too little, as whatever you gain in power savings you’ll promptly lose
to increased disk paging.
Apple’s MacBook
Air offers 4GB of RAM, but most of the systems from Dell, HP, and other OEMs
start at 8GB, and I think that’s the better sweet spot. That’s not to say you
can’t get by on 4GB — you absolutely can — but 8GB gives you a bit more
breathing room. What about 12/16GBs of RAM? Have you tried a PC with that
amount of memory?
There’s at
least some evidence that modern desktop applications have slowed the rate at
which they demand 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
16 years to match this early rate (from 64MB in 2000 to 2GB in 2016).
A lightweight system
today can get by with 4GB of RAM. 8GB should be plenty for current and
near-term future applications, 16GB gives you comfortable space for the future,
and anything over 16GB is likely overkill unless you specifically know you need
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, but DDR4 has already begun to
replace it on the mass market. If you’re building a new system and don’t have a
specific reason to use DDR3, we’d recommend buying hardware that’s compatible
with DDR4 and of course, for new complete systems, this is going to be a standard.
With that said,
if your system does use DDR3, that’s not the problem that it used to be. In the
old days, a computer stuck on, say, PC133 SDRAM was at an intrinsic performance
disadvantage compared with systems that used DDR, particularly at higher clock
speeds. That’s less true than it used to be, and it may make sense to upgrade a
DDR3 system depending on what you have and when you bought it. The reason to
use DDR4 at this point has more to do with long-term memory pricing trends and
future compatibility than fundamental performance. We’ll explore current price
and the performance question later in this guide.
DOES FASTER RAM BOOST SYSTEM PERFORMANCE?
Short answer:
Sometimes, but not by much.
Medium answer:
It depends on other system components, workload, and whether or not you’re
using integrated graphics.
Longer answer: ….
RAM performance
is controlled by two metrics: Clock speed and access latency. Access latencies
tend to fall much more slowly than clock rates, the memory cell cycle time of
PC100 is roughly equivalent to DDR4-2133. DDR4 doesn’t match DDR3-2133 cycle
times until you hit DDR4-4266.
Conventional
wisdom is that RAM latency has become relatively less important in recent
years, thanks to a combination of factors. Back when L2 caches were small,
memory controllers were off-die (and clocked at a fraction of CPU speed), and
there were no L3 caches, memory latency had a larger impact on overall system
performance. Modern CPUs are typically backed by 512 to 1MB of L2 (per core),
and 1.5MB to 2MB of L3 cache (per core). Memory controllers are now integrated
on-die and run at full processor speed. As a result, RAM latency simply doesn’t
play as large a part as it once did in determining performance.
As for raw
memory bandwidth, the same large caches that minimize the impact of RAM latency
in most applications also limit the impact of memory bandwidth. Desktop
applications are, for the most part, latency-sensitive, not
bandwidth-sensitive.
WHAT ABOUT HIGH-END GAMING PERFORMANCE?
Until recently,
I would’ve told you that high-speed RAM had very little impact on high-end gaming
Digital
Foundry’s tested a Core i5-6500K with a GTX Titan X at 1080p in a variety of
titles to measure both the impact of overclocking DDR4 and of higher clock
speeds. What we’ve done below is map the gains they saw from overclocking DDR4
from 2133MHz to either 3066MHz or 3200MHz. These two 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 improvement.
Battlefield 4,
Crysis 3, and COD Advanced Warfare all see gains under 10%, while GTA V, Far
Cry 4, and The Witcher 3 are all at or above the 15% mark. Assassin’s Creed
Unity splits the difference, with a 15% jump in minimum frame rates and a 6%
rise in average frame rates.
The Digital
Foundry team claims to see 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.
Intel chips
gain more than AMD does from faster DDR3. This actually makes sense — the
FX-8350’s L3 and integrated memory controller are clocked at 2.2GHz, and the
FX-8350 has other latency issues that will blunt the impact of faster RAM.
For years,
conventional wisdom has been that RAM clock speed is nearly irrelevant to game
performance, provided that you’ve met the minimum threshold for a title.
It’s possible
that we’re seeing the impact of new game engines or that the GTX Titan X was
powerful enough to show an impact, whereas previous video cards were not. The
choice of resolution (1080p) and potentially even the use of FCAT over FRAPS
could also have played a part.
One major point
to be aware of if you intend to try and run extremely high memory clocks: If
you’re buying a bunch of DDR3-1600 (or DDR4-2133) to stick in a box, you
probably don’t need to worry about sticking to the “manufacturer recommended”
section of your motherboard manual. If, on the other hand, you want to run
maximum clock speeds, take the time to review precisely which RAM your motherboard
vendor recommends you use. Keep in mind that running high RAM clocks is often
at odds with running large amounts of memory. Single-sided DIMMs tend to
tolerate high frequencies and low latencies better than double-sided memory,
and you ideally don’t want to use more than one DIMM per channel unless your
motherboard vendor specifically recommends differently.
UPGRADING & COST
Before we
discuss the upgrade question, let’s have a look at what you can expect to pay
for DDR3 and DDR4 today. We compared the price of 16GB of DDR3 and DDR4 memory
throughout their respective clock frequencies (Newegg.com as reference).
DDR3 prices are
fairly stable until you reach DDR3-2666. DDR3-2400 may be worth the extra
dollars, since you’re paying 18% more and receiving a 50% clock boost, but
nothing above 2.4GHz is worth your cash.
The rapid price
increases above 2.4GHz don’t just reflect enthusiast price gouging, but the
difficulty of getting good yield on DDR3 memory at these frequencies. DDR3
wasn’t designed to scale to such high clock rates, and the 2666MHz price
reflects that.
DDR4-Scaling
DDR4 shows a
more leisurely curve. There’s no single inflection point at which cost
skyrockets. $105 for 16GB of DDR4-3200 isn’t a bad deal if you can spare the
cash, 16GB of DDR4-2133 isn’t going to leave you gasping in the latest games.
SHOULD YOU UPGRADE OLDER SYSTEMS?
Upgrades are
another area that deserve consideration. There are plenty of first-generation
Core i7 systems that likely opted for DDR3-1066. If you’ve got a Core i7 rig
from this era with 4GB to 6GB of relatively low-speed DDR3, is it worth
upgrading to high-speed RAM?
The answer here
is probably, but I wouldn’t go overboard. 12GB of DDR3-1600, for example, is
around $60 at Newegg. Higher frequency kits aren’t always offered in the
multiples of 3 that the old X58 motherboards liked best, but if you can find a
DDR3-1866 kit that matches your board and doesn’t cost much more, I’d say go
for it.
DDR3-2133
should be considered the highest-end “practical” upgrade clock for older
hardware. If you’ve already got 8-16GB of DDR3-1600 I wouldn’t bother, but if
you opted for DDR3-800 to DDR3-1066 when you built your system and have just
4-6GB of memory in it, you may see some modest improvements for relatively
little cost.
PUTTING IT ALL TOGETHER
If you’re
planning to buy a new laptop, check to see if it allows for RAM upgrades or
not. Mobile users with light use cases can get by on 4GB of RAM; 8GB is a good
target for the majority of people. If you’re a gamer, photo/video editor, or
planning to do CAD/CAM work, we recommend at least 16GB of memory. If you need more than that, you already know
it.
If you’re a
desktop user with an older system, especially an older enthusiast rig, adding
faster RAM may help you eke a few more years out of your hardware, especially
if you only have 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, but don’t worry
about your rig being crippled if you need to shave a few dollars off the cost.
DDR4 will be on the market for years to come and the prices will inevitably
come down further. This is particularly true if you’re going to build with a
midrange GPU; a GPU-limited game won’t see a huge performance shift from using
faster DDR4.
If you want to
install massive amounts of memory now, there’s nothing wrong with jumping from
8 -> 16 -> 24 -> 32GB
of DDR4, but I don’t expect it to be 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 time. If you’re planning to
edit 5K videos or RAW 4K camera footage this obviously doesn’t apply to you.
And some final words…
Did you already test your PC (desktop or laptop as
well) after a clean install of the OS and check how much RAM consume without
any installed applications? Of course, the OS will give you different results
and depends if it is x64 or x86.
Always remember: the 3 major components that will be
hand to hand are: MOBO, CPU & RAM
IT IS HELPFUL? LET ME KNOW YOUR COMMENTS
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