X60s vs X60 - undervolting and battery life - vs X60t

[lenny_pl]

Hi, I'd like to buy my second X-series Thinkpad. I'm very pleased with build quality of my 10 years old X21, but it's obviously too slow for today's computing.

For almost the same money I can get:
1) plain-vanilla X60s with an Intel Core Duo (Yonah) L2400 1,66GHz (slightly more expensive)
2) X60 with an Intel Core Duo (Yonah) T2400 1,83GHz, bluetooth, built-in HSDPA modem and fingerprint reader (a bit cheaper).

The thing is that these additional equipment would rather be used in the future (modem) if at all (BT). However additional cost would be significant.

Despite it, I'd go for a second one, but I'm really concerned about battery life.
Considering that both cpus can be undervolted (I know that lowest multiplier is locked), is there any possibility that undevolted T2400 will consume more or less the same amount of energy as also undervolted L2400? Will the difference be significant enough to resign from nice gadgets? Does low voltage cpu makes a difference when you take undervolting into account?

At Thinkwiki, in Core 2 Duo (Merom) section there's a paragraph that says:

As you can see, the Low-Voltage CPU's work at the same Voltage as the normal CPUs when running in SLFM. With a simple tool (RMClock) you can use those lower voltages at every clock. [...] With SLFM and a little bit luck, you're T-CPU can be thriftier than a LV-CPU but has more power.
http://www.thinkwiki.org/wiki/Intel_Cor ... ow_Voltage

But AFAIK SLFM was introduced in Meroms, Yonah's successors, and there's not a single word about undervoltage at Yonah's page. Do the differences between L2400 and T2400 are more significant? I'm eager to find out

I'll be thankful for every knowledgeable answer.
Yours faithfully,
lenny_pl

PS I have no idea if X60s is ultralight one. I guess it is not, but I'll ask the sellers about type number.

PS1 Do you have any advice for buying used Thinkpad? I'm certainly very concerned about quality of the screen - in terms of key imprints and discolourations (bad pixels are somehow quite rare). Good looking bezel is also quite obvious. But anything else I should be particularly aware? Any quirks?


EDIT - Here's link to the compare table - http://ark.intel.com/Compare.aspx?ids=27229,27235,
Voltage Range for L2400 1.0V - 1.212V
Voltage Range for T2400 1.1625V - 1.30V
Max TDP for L2400 15 W
Max TDP for T2400 31 W
At this forum I found one relevant thread - http://forum.thinkpads.com/viewtopic.php?f=30&t=21614

At the same clock speed, a regular T-Core Duo and L-Core Duo will have the exact same performance. Due to the higher voltages, T-series can clock higher and thus attain higher performance. But higher voltages = more power consumption & more heat.

I would just get a T chip and undervolt it with RMClock...
then you get higher clock speeds and longer battery life

I'll PM lithium726 later - maybe he has some field experience with that matters

I also found short discussion at other forum - http://forum.notebookreview.com/showthread.php?t=56042

post #4:
CoreDuo T2400
0.962v @ 1.83ghz
Full load = 53c
RMClock
post #11
My temps dropped about 5-7c. Battery life remians unchanged, because the CPU already defualts down to .950 when on battery.

post #16:
I have it set to the following:
1000Mhz: 0.950v
1166Mhz: 0.950v
1333Mhz: 0.950v
1500Mhz: 1.000v
1666Mhz: 1.025v
I can feel the temperature difference. My battery life seems to have improved slightly at higher speeds but obviously not at all on lower speeds.

post #18:
And I benchmarked it at 1.83 ghz(T2400) and at 1 ghz, and benchmarks were practically identical. Undervolting doesn't really seem to help unless you are encoding on battery or something and your processor is constantly at its max speed.

So, I'm quite puzzled - does undervolted T2400 can be on a par with L2400 in terms of battery life?

[sojourner]

Hello lenny_pl, welcome to the forum!

By the length and content of your post it is obvious you really want to make the right decision choosing a laptop. I own an X60 (2GHz model, 3.1lbs, 1.4 kilos with battery). Never had the 's' model so I cannot give you a direct comparison, but can offer this:

In my experience I've never heard undervolting makes the battery last longer, but I know undervolting can make the laptop run cooler because excess voltage is often dissipated as heat! But here's a twist, as the laptop runs cooler the fan may not come on so much which means conserved battery life , BUT if you use a good fan control program and set it up properly you'll also conserve battery power thus making the battery last longer. So what do I do? BOTH!

Found NHC (Notebook Hardware Control) to be the best software for undervolt and fan control in XP. Btw one other thing, the WIFI card my TP had (past tense) drew a LOT of power. It was the Lenovo Atheros 802.11a/b/g/n. Power consumption on battery rarely went under 10w. Changed it out for an Intel 802.11b/g and now watts go as low as 8. Don't use 'N' networking but the common 'G' so it was no loss. And wow, there was quite a difference in power consumption (I think the N card has more transmitters), so the WIFI card you choose can really make a difference in battery life, and it sounds like you have a concern for that. One other big issue, if you do mainly non CPU intensive computing (email, web surfing etc.) you'll likely see little difference between the two models. If you do CPU intensive work (e.g. multimedia production, extreme graphics etc.) you see a big difference (15w draw compared to 31w). What type of work will your TP be used for? It makes a difference. So to answer your statement; "So, I'm quite puzzled - does undervolted T2400 can be on a par with L2400 in terms of battery life?". It likely depends on what type work you'll use the TP for!

The last thing I'll comment on (for now) is buying a laptop:
I've had many experiences buying and found about 50% of the time I was disappointed. Sometimes one persons perspective of what 'good' is can be different than yours. So when you look at a description you're really just looking at that persons perspective, and hopefully they're being honest! Of course this regards looks ... the other issue is functionality.

I often ask direct questions, like:
1. does everything work properly
2. is anything broken
3. is anything missing
you get the idea!

And of course when you receive the TP run all tests using Lenovo's PC Doctor. If it passes all those, that's good!
Buying on ebay is a risk (I've often been disappointed with laptops from there), buying from a known forum member here is far less risk!

[pershing]

Hello,
Nowadays I have both X60 and X60s, It seems that x60s consume less power than x60, but I'm not 100% sure > I realized that from power manager - both batteries have almost same capacity (~24wh) and x60s shows more time remaining at same config (max battery life)


Other difference is that x60s is lighter and slimmer than x60 - but this is also listed on lenovo page

I think the x60s is better but I'm staying with my x60 for now.
If you have more questions just ask.

[tim S]

Of course to get a real evaluation one has to find someone with both an X60 and an X60s. Not easy to find!
I went with two used X60s based on reviews and the fact that up to the present the X60s has the longest battery life of any laptop, about 7 hours with an extended battery.
Whether this is just wishful thinking, or the test was done doing nothing with the laptop until the battery died, it is safe to say that my X60S gets 2.5 hours on the regular battery and about 3.5 on a relatively old 8 cell battery, without dimming the screen or using any battery saving measures at all.
The X60 has a full blown processor while the X60S uses a low voltage one. Based on that alone the X60 may be a smidge faster but it takes a little more juice to run and may get hotter than the X60S.

Tim S

[lenny_pl]

Thank for very insightful replies!

In my experience I've never heard undervolting makes the battery last longer
if you do mainly non CPU intensive computing (email, web surfing etc.) you'll likely see little difference between the two models. If you do CPU intensive work (e.g. multimedia production, extreme graphics etc.) you see a big difference (15w draw compared to 31w).

Because I've no experience with overclocing/undervolting/etc. that's what is puzzling me - I assumed that TDP is strictly corelated with voltage settings. I thought that setting them at the same levels in L and in T should in effect give the same energy usage and consequently battery life - that two cpus become alike, even at higher multipliers, thus max TPD will be pretty much the same.
But it's very soothing to hear that low-intensive computing reduces the difference - cpu certainly won't be squeezed out.
Power drain from other devices - well, I'll do what I can when I'll finally have one

both batteries have almost same capacity (~24wh) and x60s shows more time remaining at same config (max battery life)

Could you, please, give some more details? How many minutes does more mean?
And as you mentioned size - do you have, so called, light version of X60s? That would definitely alter the power usage.

it is safe to say that my X60S gets 2.5 hours on the regular battery and about 3.5 on a relatively old 8 cell battery

By 8 cell battery you mean 5200mAh and by regular - 2600mAh? Relatively old - how many capacity available does it mean?

Thanks again for your time!

[MiRacL]

Hello

I had a X60s earlier in 2009, switched it out for an X60. Mainly because becaus my x60s didn't have bluetooth or fingerprint reader.

In my experience the X60s is a litte lighter and doesn't get as hot.
When it comes to battery life im no certain, i've never used the battery until i ran out.
How much loger battery life are you expected to get out of undervolting the cpu?

In ubuntu one can set a static cpu speed. The cpu uses intel speedstep and clocks up/down as it wants. I ubuntu i used to lock the cpu to 997mhz and the computer wouldnt get so hot.
This is probably possible in Windows as well.

I would go for the X60 and install an SSD drive in it.

Both the "T" and "L" cpu's are Yonah's, so i would imagine a 1.83ghz cpu clocked down to 1.66ghz could use the same voltage.

If possible, just lock the cpu to the lowest speedstep speed and the voltage will also drop.
My 1.83ghz uses 1.263v @ 1.83ghz acording to Cpu-z.
@ 997 mhz it uses 0.950v acording to cpu-z.

If i lock the cpu @ 997mhz i would imagine the battery life would be longer, but the performance would go down.

[shhhpad]

My experience undervolting my L2400 indicated that you could only see about a 10% improvement in battery life under Windows. Here are a few thoughts.

Reducing the voltage will reduce the overall power consumption (TDP is correlated to wattage) of the processor at a given speed. Wattage is power consumption. As it is calculated by Volts * Amps, you see a TDP difference between the two processors even on the same voltage due to the lower amp spec of the low voltage L2400.

For the T2400 and L2400 I've noticed that they simply do not have very much room to undervolt. It's already set to the lowest voltage at the lowest clock speed so what you end up doing is reducing the 1.86ghz or 1.66ghz clock speed voltage slightly - which does help - but not by much and only under load. These processors are so fast for everyday usage that they're almost always clocked down.

Also, many of the utilities that do the undervolting also do things like enable enhanced sleep states (C3 & C4) and actually end up getting in the way of the excellent lenovo power manager driver by trying to manage the clock speeds on their own -- increasing CPU usage. So, at the end of the day, you end up with about the same power consumption because the processor doesn't support very low voltage like the desktop processor usually do. And the benefits of the lower voltage are only realized under load.

Disclaimer: in my experience, you see a lot better results undervolting under linux.

Anyway, if you're looking for the best power battery runtime I would without a doubt recommend the low voltage L2400. It is plenty fast for most people (a lot faster than an Atom!) and a lot cooler as well. On my X60s I am able to literally peg the processor for playing a 3d game (that the gma can handle) for three hours until my 8 cell (5200mah) battery runs out. On a T2400 there is a about twice as much heat and power consumption. Keep in mind I play pretty old games. So it's actually a lot more comfortable to use on a daily basis than my other X60 with a T2400.

Regarding the difference between the two processors undervolted on the same 5200mah battery, I have a T60 with a the T2400 on a 5200mah battery and it runs for about 50% less time than the X60s with the same battery under load. Now, on a X60 running a T2400 I only see about a 30% difference, in my experience. My experience indicates the T and X series are on different chipsets, displays and so on the other 20% or so is up to the design of the laptop. I can assure you that the low voltage processor is responsible for most of the savings through a lower consumption of the processor itself and the reduced need to run the fan under load (my x60s fan never turns on unless I'm doing 3d graphics stuff).

So, there are a lot of things that contribute to power consumption to keep that in mind when you're looking at the L2400 vs T2400 machines as the low voltage processors have battery life as a priority so they're paired with chipsets and displays that consume less power. Intel has done a great job with their low voltage platform and while undervolting the X60 series might help a little bit, it dosen't do much in practice because you're only working with only one variable of a complicated system. As far as the smaller X60s verses a T60 the difference is remarkable due to the design goals of the machine while the benefit of an X60 over an X60s is less noticeable.

I think if you're buying an X-series you shouldn't be expecting to encode h.264 at any great speed even on the fastest X60. Given the choice, I would rather have a slightly slower X60s that runs cooler and quieter over an X60 that's a little bit faster only part of the time and bothers me.

But the X60s costs more. Hope this helps.

One last thing, about the screens... I buy two or three used 60-series thinkpads per month and I never really see dead pixels but I do see a difference in the backlight wear between models. I fix that by replacing the backlight and inverter modules though.

[pershing]

Could you, please, give some more details? How many minutes does more mean?
And as you mentioned size - do you have, so called, light version of X60s? That would definitely alter the power usage.

I think it was around 20-30minutes difference...but I have to test it completly and I'll write here

[lenny_pl]

@ MiRacL
Nice idea - locking cpu when you e.g. browse web, read mails, etc. Thanks!

@ shhhpad
Great, matter-of-fact post! Thanks for reminder about getting in the way of Lenovo's own power manager - one should really think it through on XP. However I more often use Arch Linux and it's nice to know that undervolting would be more effective.
Another good point - X60s were probably constructed from better parts, so not only low voltage cpus make the difference.

@ pershing
Thanks for numbers! I think that data will be sufficient. Mainly because I found a new contender


Seller of X60s put on auction another bunch of Thinkpads - X60t. Price is substantially higher but... when you divide the overpay by 156 weeks (but I'm certain I'll use it much longer) it will cost me more only equivalent of one beer every week and I really can live with that

What are the advantages of X60t?
- SXGA screen (1400x1050) - it's not a multitouch one, but AFAIK that means only that I can only use stylus - I guess that's fine - it's neatly hidden and easily accessible.
- L7400 Merom cpu - with mentioned above SLFM and more cache memory.
- Lenovo guarantee until 12-06-2010 - but I'm not really sure if it's so important (other ones come with sellers own guarantee).
- It also has bigger hdd (100GB, 7200rpm), bluetooth and fingerprint reader. Lack of modem probably can be solved with my cellphone acting as a one.

What's bothering me?
- Hinge - will it last for a long time of careful use?
- Screen wear - I have no experience with touchscreens - on pictures it looks great - what's the catch?

I'm waiting for a mail from the seller and I'm starting my own research on tablets so probably more questions will arrive - I hope I won't overstay my welcome

PS - Did you know that Paul Krugman has X61? http://krugman.blogs.nytimes.com/2010/01/28/whypad/

[j-dawg]

The SXGA+ screen is beautiful. It's the main reason I picked the tablet over the regular X61 or X61s and it's been totally worth it just on its own. All those pixels and a great panel. It's just a bit dim, but besides that it's great.

I haven't noticed any problems with the hinge. There's one or two mm of play all the way at the end of the screen now, but that's after nearly two years of use.

The tablet features I find myself using rarely. But I haven't had any problems with wear.