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swampfox · Wed Apr 27, 2011 7:26 am

Looking at a Lenovo ThinkPad Edge 420s, and I have the option of getting one 4GB DIMM or two 2GB DIMMs. In a desktop you always get two (or three) to put them in parallel, so wouldn't it be better to have the two in the laptop as well? (I'm aware of the expandability issue.)

Thanks!

derFunkenstein · Wed Apr 27, 2011 7:47 am

Take the 4GB in one SO-DIMM if it's the same price then go out and buy another just like it from somewhere else.

Generally you need 2 in order to fill your memory controllers.

Airmantharp · Wed Apr 27, 2011 7:57 am

derFunkenstein wrote:
Take the 4GB in one SO-DIMM if it's the same price then go out and buy another just like it from somewhere else.

Generally you need 2 in order to fill your memory controllers.

It's a dual-channel CPU, so yeah, get another stick. My Toshiba came with one 2GB stick and one 4GB stick, and I don't think that the size mis-matching makes a difference, but with the built-in graphics I'd hesitate to not at least have both channels going with something.

swampfox · Wed Apr 27, 2011 7:59 am

Thanks, that's what I was figuring. Was looking at another page, and they were recommending the one DIMM over the two (or at least, their little "recommend upgrades all the time" system was somehow figuring it was an upgrade...)

UberGerbil · Wed Apr 27, 2011 12:18 pm

You definitely want two sticks for optimal memory bandwidth (the exception to this rule would be AMD Brazos-based laptops, which only have a single-channel memory controller). Sometimes the price for RAM from an OEM like Lenovo is so ridiculous that if you want, say, 8GB it's actually cheaper to specify the lowest possible RAM (one 2GB stick in this case) and then remove it (possibly re-selling it) and replace it with two larger sticks (two 4GB SODIMMs) rather than spec'ing one 4GB stick and then buying a matching one in the aftermarket. Looking at Lenovo's site, it's not quite that bad at the moment, though it's close: the upgrade from one 2GB stick to one 4GB stick is $80, whereas two compatible 4GB sticks is $93 from Crucial -- and you can certainly find close to $80 on NewEgg and probably could get below that with coupons or a sale.

ludi · Wed Apr 27, 2011 1:07 pm

UberGerbil wrote:
Sometimes the price for RAM from an OEM like Lenovo is so ridiculous that if you want, say, 8GB it's actually cheaper to specify the lowest possible RAM (one 2GB stick in this case) and then remove it (possibly re-selling it) and replace it with two larger sticks (two 4GB SODIMMs) rather than spec'ing one 4GB stick and then buying a matching one in the aftermarket.

Caveat: plan to write off that OE stick as a loss, then buy beer if you actually sell it. The market for low-end sticks tends to be saturated because everybody else did the same thing.

OneArmedScissor · Wed Apr 27, 2011 1:23 pm

It will probably get better battery life with only one, which I believe is why both Lenovo and HP do that by default in all their new business models. The likelihood that you would need more memory bandwidth in a laptop is slim to none.

dragmor · Wed Apr 27, 2011 4:28 pm

You get better battery life and a lighter laptop with one stick (Lenovo's weight and battery figures would be with 1 module installed). Also the performance drop for average users isn't noticeable.

Get the single 4GB and buy a second if you notice a need for it.

grantmeaname · Wed Apr 27, 2011 4:33 pm

dragmor wrote:
You get better battery life and a lighter laptop with one stick (Lenovo's weight and battery figures would be with 1 module installed). Also the performance drop for average users isn't noticeable.

Get the single 4GB and buy a second if you notice a need for it.

Laptops can suspend for days. Therefore RAM's power consumption is insignificant. Also, have you ever picked up a SO-DIMM? Their weight is unnoticeable.

OneArmedScissor · Wed Apr 27, 2011 7:11 pm

Laptops can only run a few hours while I'm actually using them. Therefore, standby power consumption is insignificant. *face palm*

Seriously now, that's just silly and shouldn't even figure in. It all depends on how you actually use it.

Do you often use laptops unplugged? If so, use one.

Do you often use laptops to play WoW or some other 3D game suitable for laptops, with eye candy on? If so, use two.

Waco · Wed Apr 27, 2011 7:20 pm

OneArmedScissor wrote:
Laptops can only run a few hours while I'm actually using them. Therefore, standby power consumption is insignificant.

The difference between a single stick of ram with twice as many chips versus two with half as many (or one with double-stacked chips, whatever) is likely less than you think.

OneArmedScissor · Wed Apr 27, 2011 7:31 pm

You're oversimplifying and just assuming. While laptops may be different and it wouldn't be quite as significant, it drops several watts to remove one from my desktop. You're also switching it to single channel mode, halving the bandwidth, and taking additional circuit boards, traces, connections, blah blah blah out.

The fact of the matter is that two memory channels is not really beneficial in almost any case, while laptops of today spend most of the time running on only about 5-6w, and taking off a fraction of a watt there can give you a decent chunk of battery life. They're all running 1333 MHz RAM now and there's plenty of bandwidth to go around.

Waco · Wed Apr 27, 2011 7:49 pm

OneArmedScissor wrote:
while laptops of today spend most of the time running on only about 5-6w

Citation needed.

Wed Apr 27, 2011 8:11 pm

TheWacoKid wrote:
OneArmedScissor wrote:
while laptops of today spend most of the time running on only about 5-6w
Citation needed.

Mine's pulling about 30 watts right now while browsing.

ludi · Thu Apr 28, 2011 1:47 am

JustAnEngineer wrote:
TheWacoKid wrote:
OneArmedScissor wrote:
while laptops of today spend most of the time running on only about 5-6w
Citation needed.
Mine's pulling about 30 watts right now while browsing.

Got me curious, too. According to the Kill-A-Watt meter, when running on AC my Acer 1810TZ 11.1" CULV is eating about 6.3W at idle (after subtracting adapter losses and battery charging power) and my older Acer Aspire One 8.9" netbook is doing about 12W at idle. Both have LED-lit screens. Those represent some of the best-case data for laptop hardware, not average, which would be higher.

grantmeaname · Thu Apr 28, 2011 7:55 am

OneArmedScissor wrote:
Laptops can only run a few hours while I'm actually using them. Therefore, standby power consumption is insignificant. *face palm*

I wasn't arguing that standby power consumption was inherently important. Do you have any clue what standby is? It's when only the RAM recieves power. In other words, laptops' 'on' power consumption is many many times (more than 30x) higher than their RAM's is.

Seriously now, that's just silly and shouldn't even figure in. It all depends on how you actually use it.

Again, not what I argued.

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