i3 380um question

Does it make a difference whether the DDR bus on an i3 380um is populated in (identical) pairs, or is that irrelevant these days?

How much does having one stick of RAM vs having 2 sticks of RAM affect battery consumption?

 

Battery life will be slightly better with a single stick of RAM but not by any noticeable percentage.

It's irrelevant to have two same-sized sticks of RAM; it will still be dual-channel. The way that works is, say you have a 4GB and a 2GB stick - the first 2GB of the 4GB stick will run in dual-channel mode with the 2GB stick. That feature has been around for a few years now.

 

But I should still populated both channels?

I just got a Lifebook T580 and it comes with a 1x 2GB (32bit Win 7 pro).
should I be looking at 1x1GB; since 32bit OS don't use 4GB?

 

Yes, both channels should be populated. You could still go for a 2GB stick depending on pricing, i'm pretty sure 1GB SODIMMs are hard to find these days.

 

Contrary to popular belief, I would recommend 4GB for even 32bit systems - just for the 'exact/identical' modules that would ensure and in addition to the dual channel symmetry for all the RAM the O/S can use (some systems can use up to 3.5GB RAM or more, depending on the exact MB and other specific hardware installed).

As for any extra battery power used with additional SoDIMM modules's, it will simply cancel out with the added benefits the extra RAM brings to the system (by using and relying on the HDD that much less...).

Hope this helps.

 

I also recommend 2GB, but only because the 1GB sticks are likely close in price to the 2GB sticks and therefore makes it a no-brainer.

Some 32-bit systems will recognize slightly more RAM (e.g. 3.1-3.3GB). And you have to consider the fact that someday you might install a 64-bit OS.

 

Thank you all for the feedback, much appreciated.

I have a slightly different question.
If the CPU that comes with the Fujitsu T580 is an Arrandale, can it be replaced with a sandy bridges or are the motherboards incompatible?

On a slightly related topic, I'm confused about Max TDP. That's the most heat the system will tolerate or the most amount of energy the unit consumes?

 

Incompatible motherboards. TDP represents the maximum amount of heat output, guaranteed by Intel, that the CPU will produce. It is used by manufacturers to design adequate colling, well manufacturers that actually do a good job of designing notebook cooling. A 35W core i5 will produce 35W of heat when fully utilized.

 

If I understand correctly, that means that there is no upgrade worth the trouble for an i3 380um as the only other two models (i5 & i7) are nearly identical with the exception of 1MB more of cache, turbo boost to 2GHz+ and the addition of AES (whatever that means). All in all, upgrading CPU doesn't seem like a financially worth while investment for this line of CPUs; it wouldn't even lower the Max TDP


Does Max TDP implicitly define power demand? I often find reviews that compare Max TDP in a way that seems to correlate it with energy consumption (or battery life efficacy).

 

Well, a CPU with higher TDP, usually means more power consumption as well, but the TDP isn't the same thing as the power consumption, they are related though. The switch from an i3 to an non ULV i7 might be worthwhile, since the i7 has 4 real cores, the i3 only has two hyperthreaded cores. However, the i3-380um is a low voltage unit with a TDP of 18W and the non ultra low voltage i7s have a TDP of 45W for the 720/740/820//840qms and a TDP of 55W for the 920/940xm. I highly doubt your laptop could handle the extra heat dissipation so in your case, an upgrade is not something to consider.

Your CPU is still quite fine for office work and internet browsing.

 

TDP is a number Intel provides to tell manufacturers how much thermal energy the heatsink they pair with the processor needs to be able to dissipate. It's not directly tied to the processor's actual power consumption as tijo said. Related, but not scientifically.

 

Well, with the right tools, i'm pretty sure you could establish a temperature dependent TDP/Power consumption relation. Maybe someone already did it.

 

You could, but consider the fact that (for example) the dual-core i3, i5, and i7 all have the same 35W TDP. There is no way the i7 does not consume more power yet it is rated the same.
And even within processors, I know from my Pentium M undervolting days that chips are not created equal and there are voltage differences within the same model chip.
Perhaps you could get it down to something - using your suggested method - like "for the dual-core Core i-series, the actual power consumption is 80% of the TDP +/- 5%" (those are fictional #s of course).

 

Yes, you'd need different models for the different lines of CPU and testing would have to be done at the stock intel voltage values too. I don't expect the relation to be linear either as power consumption in electronics is related to temperature which is related to power dissipation and power dissipation is related to power consumption. I do know that the value reported by HWiNFO32/64 in the PCH section is closely related to TDP though (i have absolutely no idea how it is related to power consumption on the other hand). I tested it with my 920xm and as soon as the value went over the specified max TDP, the clocks went down to non turbo multipliers.

 

Hm. That's a good point about Turbo Boost. I believe that only engages if the temperature is within a "safe" range. IDK how/if TDP plays into that.

More variables to this than I thought!

 

Yes indeed, You can be certain that TB will kick in if you are under 100C (at that point you'll go back to the lowest possible multiplier). On the first gen core i, TB isn't allowed to go over the TDP, that is why for example running prime95, 8 threads on my 920xm at 55W TDP results in a multi of 15 to 16 instead of the turbo at 17, if i set the TDP at 65W (being able to specify the TDP on xm CPUs is awesome ), it's at a stable x17 multiplier.. On Sandy Bridge, the CPUs are allowed to briefly go over their TDP until they either finish the task or the specified amount of time runs out. Aside from architecture refinement, this one reason why you see more aggressive turbo ratios on SB CPUs.