Sager NP8690 -> 720qm or 820qm?

I kind of want to validate an what I have been researching and this place has been great to me so I ask it here-

I am thinking of getting the 720 over the 820 due to it not affecting game performance but like a frame or two accross the board. Will save me a nice chunk and still perform great.

Is this a bad idea?

I base this on what I read here and also here -> Notebookcheck: Review Intel Core i7 Processor "Clarksfield"

Am I making a mistake in 'downgrading'?

 

Not really a mistake, no, although I'd pick the i7-620M over the i7-720QM. Even the i5-520M is quite a solid gaming CPU.

 

The i7-620M is probably faster and better than the 720QM now, but i'd go with a quad core as its more future proof with games. the 720qm and 820qm do not really have a very noticeable performance difference so i feel its about whether you can afford it, if so the 820qm is actually worth the little $150 extra. I have a little regret not getting it.

 

When you are playing RTS games like SC2, the CPU prowess will show.

But if you are mostly playing FPS games, an i5 520 even would be enough.

 

Based on your choices, I'd go (I personally did) with the 720 as it's cheaper. If you play GTA4, go for the 720. The margin that you'll pay for the performance enhancement is, imo, a bit high at the moment.

BUT if you can burn away money, then by all means, go for the 820

 

I am doing the 820 after a lot of reading.

Reasons being- the 820 is the first quad better than a duel core in benchmarks. If I wanted the 720 I'd just get the duel core as it benches better. So the 820 is the sweet spot for me.

I want a quad and way down the line I can drop in a better quad.

 

But doesn't Arrandale use the same socket as Clarksfield anyway? There might be differences in the BIOS so you should check with the retailer, but if you're going to drop in something better than the i7-820QM later (though there won't be anything much better, just the slightly faster i7-840QM with 133MHz extra clock speed as far as I know - though prices might drop) it would make good sense to save money now.

 

840QM will not be that much better. The difference between 820QM and 840QM will mit minimal - 133MHz, thats it. The 920XM and 940XM will keep their high prices. So buying a dual-core now to upgrade to a quad-core later will not save you much money. If you need the quad-core just buy it now, if you are fine with a dual-core, just buy a dual-core.

 

good choice, i got the 720 and wish i got the 820

 

Why do you wish you got the 820?

 

I'm glad I got the 820 as well, simply because everyone and their mom are using an i7 720. Though I still wish I've gotten an i7 920XM ES instead, same price as my 820QM.

 

I actually think the 820QM is a bit better. The cooling of the W860CU and W870CU is quite good as we know. I did some tests on the Turbo Boost. When I ran ORTHOS (uses all four cores) and Furmark (to stress test GPU) together, the 820QM still uses Turbo Boost and overclocks all 4 cores to 2,0GHz (1,73 + 0,133 + 0,133). The same applies for the 720QM but the 1x Turbo Boost can only overclock it to 1,73GHz (1,66 + 0,133). So it's 2,0GHz against 1,73GHz. So actually a bit more than 1,6GHz vs. 1,73GHz (plus the bigger cache). It would also be interesting to know if the 920XM really uses Turbo Boost to overclock itself under load or if it stays at the standard 2,0GHz because of the higher TDP. In that case there would be no difference between a 920XM and a 820QM.

 

If anything, having a 820QM will improve the saleability of the laptop when the sandy bridge upgrade comes around and everybody is trying to get rid of their system.

 

What did you use to monitor the multiplier / clock speed? Not all applications can reliably detect what's going on with Turbo Boost.

As for reselling, you're paying $220 extra now, but the difference in resale value will be much less.

 

the turboboost is correct, 820QM has a higher turbo boost multiplier that is same as the 920XM, at 4 cores, 820 will turbo boost to 2ghz, while 720w will turboboost to 1.73ghz. at 2 cores, 820 will get to 2.8ghz, while 720 2.4ghz.

 

I look at it this way, you will be able to fetch a better price than an equivalent 720 equipped system, maybe 100 bucks if your lucky. It will probably sell faster being a better spec system. Finally You will have had a faster processor to enjoy during that time

 

I know those are the correct multipliers, but Turbo Boost also has TDP and thermal limitations that might stop you from consistently running at the maximum multiplier. For example, my i5-430M is specified at +2 Turbo Boost across the board (4/3/2/1 threads), and will consistently sit at 19 (2.53GHz) when heavily loaded on up to 3 threads, but I find that when running 4-thread wPrime RealTemp reports the average multiplier as 18.9 or so, and when running 4-thread Prime95 it's reported as 18.3 or so. What actually happens is that the multiplier changes many times a second, and so the standard way of just reading what the CPU reports as its multiplier is often inaccurate.

The faster CPU is only really going to help for tasks like video encoding, though; otherwise you won't really notice the difference between the CPUs. I wouldn't be so sure about it selling faster either - the point of buying a second-hand system is low price.

 

I have the 920 in my 8760 and ran some cursory testing to satisfy my curiosity of where my machine stands in the performance and heat envelope for the uses I have for my machine. The main game I run is single threaded and will max out a single core at 100% all the time. With my 920 using Eleet I can force an overclock to 3.73GHz and run all day long on the single core and not reach the 85 degree threshold at which the Sager will start to throttle down the clocks. Conversely I can run a prime program that uses all 8 cores and force an overclock of 2 bins over the 2 GHz and it will stay at that overclock till it gets ups to 85 degrees at which point it throttles down to 2.13GHZ and stays there. My temps will hover around the 85 degrees with al 8 cores at 100%. I have stock paste and cooling so If I can do that It should be even easier for the 820 to run at its max potential turbo modes without reaching the higher temps I do. There are other people on here that have gotten similar results as well.

 

RealTemp / i7 Turbo is a better way to see what's going on with the multiplier, since it probably doesn't sit at exactly 2.13GHz.

However, the Turbo throttling isn't just temperature based. When getting the figure of 18.3 I mentioned earlier, the CPU cores were running small FFTs in Prime95 and only at a temperature of 73 degrees or so - clearly the temperature wasn't the reason I wasn't getting the full boost.

According to Intel,

Considering that the i7-920XM is rated at 55W TDP while the i7-820QM is rated at 45W TDP, they could easily behave very differently with Turbo Boost.

Besides that, Turbo Boost behaves differently to manual overclocking. Have you tested your i7-920XM with stock clocks and Turbo Boost enabled to see what it will do under varying levels of load?

 

Lack of cheese:

I was using Realtemp/i7 turbo when I was performing my tests, and I was logging into a .CSV file to look at the results.

The biggest problem with your argument is your trying to compare your experience on a i5 430 to what this thread is talking about the i7 Quad’s. Your processor experience doesn’t even share the same spec sheet with the i7 Quads. (Let me use a metaphor, your comparing oranges to apples, I am comparing a red apple with a green apple) Also unless your testing on either the 8760 or the 8690 your again not able to compare your results with what I am seeing. Each laptop manufacture has different approaches to the how the Bios controls the ACPI of a machine, and that affects the behavior of throttling and at what level the TDP is allowed to operate at.

I seriously doubt the behavior difference between an 820 and 920 would be significant just based on TDP. The true nature of how turbo boost exactly operates is not published for public consumption (there is a lot of info that is only available to developer) we can try and characterize it the best we can. I do not have access to an 820 nor do I have the time or inclination to spend a lot of time on this as it really is not that important to me. I know there are a few posts from soviet in the owners lounge for the 8760. He spent some time characterizing how turbo work, and if I recall he had the same results I am seeing. Also how it operates is more sophisticated than the simple explanations Intel give us.

When I first ran my test they were without manual overclocking and the behavior was in fact the same for me.

Just for your future reference I do know what I am doing with computer hardware, I design electronic systems for a living. This includes micro technologies along with power supply, analog and RF. I work at a small company that means we have to know a lot about the different disciplines. That is one of the reasons I do not want to spend a great deal of time methodically characterizing what we are talking about, I do that kind of work 8-9 hours a day.

 

75°C!? 85°C!? In what environment are you running your laptops!? Even with stress testing my 820QM does not go above 66°C and thats with standard thermal paste (plus it's 26 - 30°C and high humidity right now in Istanbul). You still use that black sticker in front of your CPU fan?

 

my CPU reaches max of 78C after 10min of prime95 torture test on all 8 threads. The turbo boost remains at 2ghz until 72C, where it drops to 1.86ghz, but still turboboosting, even till the max of 78C.

Though in normal usage, the CPU never got above 60C.

 

It's not a "bad" idea, I would personally take the 820QM, but that's me. If you really need to save the cash go with the 720QM then, it won't hurt you much.

 

Well, othonda, it seems like the i7-820QM can't quite consistently run at its max boost either. All I was trying to say is that your experience with the i7-920XM doesn't give you any guarantees about the i7-820QM, and we've seen that prove true.
There is definitely a lot of hidden complexity to Turbo Boost, and I would love to know more about what happens behind the scenes, though.

 

After 20 mins of prime95 on my CPU which is the same as yours, most Cores are at 70-71C and one Core is at 73C. The Turbo Boost behavior is similar to what you described. During gaming and normal use temps are usually around the 60's.