2720QM vs 2820QM vs 2920XM

There is a noticeable drop, but it is still much smaller than the drop in price -- the 2630QM is a little over half the price of the 2720QM.

 

After a lot or research I've decided on the 2720. The difference is so slight between the 2720 and the 2820 that I don't think there is any real world benefit and the 2920 is waaaay up there in price, so not a great value right now, maybe later when prices drop.

 

or you could get a 2920xm es/qs off ebay at 1/2 to 2/3 the price when they become available

 

I went for the 2MB cache.. let's see how this turns out in the long run..

haha..

 

What are they compared to QX9300?
Do all of them beat it?

 

Pretty much.

 

3.5 stable on each core simulataneously wouldn't be so impressive.. as this is attainable with the i7 920xm... i wanna see the new gen hit 4ghz across the board! But this all depends on alot of things.... if ThrottleStop cant unlock the TDP for this gen of i7... then i dont see the i7 2920xm overclocking to anywhere near that... and sadly the i7 920xm/940xm will be much faster...

Thing im worried about is how complex these cpus are getting.. with the dynamic turbo limited to 25secs, the gpu sometimes taking power away from it... something tells me the TDP on SB will be very hard to crack open because Intel won't want you messing around with all that, since so much is dependant on the TDP with this cpu.... because whats going to happen to that dynamic turbo when you OC and increase the TDP (if its even possible) itll downclock the OC every 25secs? or itll raise the already OC'd clocks even higher since the new TDP is set higher so the system will think its ok, causing those bursts of speed to crash the system... making it really hard to gauge what the max is..and potentially making the process of finding a stable HIGH OC very hard or impossible...i dunnnno mannnn its not looking too cool :S

DEFINATELY! The mid 820/840 and now the 2820qm have always screamed FAIL!! Never get the mid its sooooo not worth it... go big or go home... dont pay a premium for 100mhz in clock speeds you won't EVER notice. please please dont. And wait a bit to see if the TDP is unlockable on the 2920xm... because if it isn't... then dont bother getting that either! because theres a .2 diff between the 2720 and the 2920... which on a second thought doesn't make any sense considering the price increase... i hope its OC'ing capabilites makes this well worth it in the end...but untill we know for sure (fingers crossed).... go for the cheapest cpu for now.. and upgrade later if you reall ymust get your hands on SB right now ... either way eBay or wtv will always be cheaper than OEM xm cpus... so its a win win

note: the 840 in my sig was given to me free .. that is about the only time you should go for this cpu LOL..

ummm... bigtime.

 

More questions for you CPU-wizard types. (While I've been at this game since 8088 processors were new, all the latest stuff confuses my poor gray head.)

1) According to Intel charts, the Max Memory Size for all the i7-2x20 CPUs is 8GB. Is that per core? Or is that meaning the largest size per SODIMM (allowing 4x8GB SODIMMS in a 4 slot system for 32GB RAM)?

Compare Intel® Products

2) Again, according to Intel, i7-2620QM supports DDR3-1066/1333, while i7-2720QM and i7-2820QM support DDR3-1066/1333/1600. Just to be certain, does this mean I can run DDR3-1600 SODIMMS? Who makes those, and who has the best latency?

2a) What's the fastest RAM you've seen offered in the new Sandy Bridge laptops (17" models)?

3) Besides the 0.1 GHz Clock Speed difference, the real difference I see between i7-2720QM and i7-2820QM is that the first has a 6MB L3 Cache, and the latter has 8MB L3 Cache. Where am I likely to notice that difference? In Games? CAD? Rendering? Photo editing?

Other differences between models (no VT-d or AES New Instructions on the i7-2620QM, for example), make me think I want to upgrade from the stock series base cpu in most machines. The question is, will I be happy with spending $ for a i7-2720QM, or should I go whole hog and fork out $$ for a i7-2820QM? (I know I don't really want to spend $$$ for an XM model)

 

"(allowing 4x8GB SODIMMS in a 4 slot system for 32GB RAM)"
sounds about right, I have been seeing laptops showing up this 32GB Max capacity so I'd assume that is the case.

1600mhz laptop RAM is now being offered, but simply is it worth it? Most people can't notice the difference in speeds with 1333 over 1066 unless their benchmarking, can't comment for the brands or latency but I've heard stocks are low, maybe because of low supply but I assume it's a contributing factor of that and high demand in comparison to their stock.

 

As in the Asus N53SV I just ordered which has 4 slots but comes with the 2630QM that seems to be getting no love here.

I don't care though I'm running a P7570 not even close to the same league so it is gonna blow this thing away regardless.

 

There was a whole discussion about the same claim concerning the last-gen quads. Basically, it seems that Intel just says that because most laptops only support up to 8GB RAM.

 

Per memory controller. Two in the i7 mobiles = 16GB. I'm getting 16GB in my machine, it better accept it because it's got four slots and says each can accommodate 4GB for total of 16GB!

There's few options available at the moment. Kingston seems to be the only ones available for purchase with CAS 9.

1333Mhz

I'm not sure you'll see much difference between the 2720QM and 2820QM in most applications to be honest. The slight bump in cost ($160 for Sagers) from 2630QM and 2720QM is justified IMHO for the VT-d and faster clock speeds. But +$200 from the 2720 to 2820 isn't worth the extra 100MHz.

Just my $0.02

 

imo the i7-2720qm is the way to go. It has the extra instructions, it supports 1600MHz ram, and it has a nice clock speed increase from the i7-2630qm. The benchmarks show a nice jump in performance from the 2630 to the 2720 the jumps in performance after the 2720 are just tiny and pointless for the huge amounts they charge over the 2720. The 2720 will produce less heat and use less power then the processors above it as well.

Everyone's best bet is to go with the 2720 it offers the best value for your hard earned dollar.

 

^^^^^^^

I agree with laststop311. Obviously everyone's needs vary, if you want the overclocking option then the 2920XM is the way to go. Otherwise I also feel the 2720QM is the best bang for the buck CPU.

 

Does anybody know why the 2920XM seems to be getting such impressive wprime 32M scores relative to the 2820QM/2720QM? The 2920XM seems to be getting scores in the 8.5 sec range, as opposed to around 13 sec for the 2720QM.

 

2720qm has 6MB cache and min 2.2GHz compared with 8MB cache and min 2.5GHz. I'm sure the cache will help quite bit. Not sure what the wprime is for 2820qm though.

 

Sorry but I have to disagree. I won't even consider the upgrade from 2630 to 2720qm when the most common practice here is to charge at least 150€ more. That's about the price for a decent desktop motherboard, or the Sandy Bridge CPU that goes with it for that matter, or a capable GPU. Why would I spend that kind of money when I won't even notice any difference 95% of the time ? Maybe it's your best bet but personally I already get raped by Intel's price policy on a frequent basis, I see no point in asking for second helping.

 

Mobile Processors - Benchmarklist - Notebookcheck.net Tech

anybody knows why 2720 has higher dhrystone and whetstone than 2820?

 

2820QM is 9.9 sec. For such a short benchmark, time should be determined by the TurboBoost speeds, which for the three processors are 3.5/3.4/3.3, i.e. only about 3% difference for each step up. (This is in line with the superPi benchmarks.) The cache size might be an argument for why the 2820 is 30% faster on wprime than the 2820, but not why the 2920 wPrime is 15% faster than the 2820.

 

I meant to say that it might be an argument for why the 2820 is 30% faster on wprime than the 2720.

 

Well they don't always peak at those speeds. The highest I've seen my 2720QM go is 3.1GHz, maybe 3.2GHz for a split second.

I believe 2920XM is more likely to clock higher because it is a premium chip. Not to mention it depends on the amount of time it spends at that peak. That is part of the problem with benchmarking these new Intel chips, it can vary greatly from chip to chip even.

See here:

http://forum.notebookreview.com/sag...s-cpu-temperature-clock-speed-comparison.html

Same machines but peak and steady clock speeds vary considerably.

 

OK, now some of the wierd benchmark results start to make sense. Thank you!

This would seem to invalidate most of the preceding discussion in this thread of the relative merits of the different chips, as these were mostly based on clock speed arguments.

What's really maddening is that none of the benchmarks are published by the manufacturers, so you can't return a machine because it doesn't achieve the benchmark number some reviewer got. Basically, the manufacturers are guaranteeing absolutely nothing except for the base clock speed. That sucks.

 

Yeah, it is a bit frustrating, but brilliant marketing by Intel. Chips that overclock themselves to improve performance! Well I'm sure if they opened the multipliers for end user overclock we could probably get a consistent 2.8GHz with the 2720QM, for example, but instead users have to live with Intel's constraints on overclocking and at the mercy of whatever limits they impose.

I guess you can always get the 2920XM, but there again, it requires specific BIOS updates to unlock overclocking of that chip too, not to mention the excessive cost increase.

 

I just discovered another complication in reading wprime benchmark results: nobody says how many threads they run. I finally got my 2720QM, and was surprised to find that running wprime 32M, going from 4 threads up to 8 reduced the time from 14.4 sec to 9.4 sec.

 

Not sure if this is accurate, but I pulled up wprime 32 the other day while I was playing a game, and all my cores were around ~2.9ghz, fluctuating by a couple mhz. Don't know if it is a mistake or something, but it was holding it steady for a while.

 

yes th turbo boost in SB can keep the clocks higher if the cooling can handle it

 

Will there be any noticeable difference between the three processors when streaming video?

 

No. My SU7300 (ULV 1.3GHz Dual Core Arrandale) can stream 1080p and YouTube.

 

FYI: Kingston HyperX 1866 memory reads and runs at marketed speeds with the 2630QM and 2820QM on two different laptops from two different manufactures I've tested it in.

According to Intel this shouldnt be the case. I guess their memory specs are for what is officially supported to work with 100% reliability as opposed to this is the only spec we will let work. Also, Dell offers 16GB in a 2 dimm config on their Precision line with SB so it kind of confirms what people have said about the 8GB limit being only a paper spec as well.

 

Sorry I mean video encoding.

 

think 8gb dimms are ECC only iirc