Thinkpads Forum

When my SD card drive reads or writes data, both my sound and mouse cursor motion pause a few times each second.

Each split split second pause shows up as skips in the audio or a brief cursor motion stoppage.

This problem is very similar to older PCs that had too many devices on one interrupt. I presume this is no longer a problem with PnP and Vista.

This problem has persisted despite a full wipe and reinstall of everything a few weeks ago.

This problem even happens when using the ReadyBoost feature on a dedicated SD card. I wonder if ReadyBoost really gives much of a benefit given these apparent system pauses?

The SD card reader ist connected via PCI. IBM/Lenovo choose to use a very cheap controller chip. Accessing the reader blocks access to all other PCI devices like audio. On top of that, the CPU has to do most of the I/O to/from the reader.

I find that I get much better performance reading and writing to an SD card through a simple USB adapter.

DVormann wrote:The SD card reader ist connected via PCI. IBM/Lenovo choose to use a very cheap controller chip. Accessing the reader blocks access to all other PCI devices like audio. On top of that, the CPU has to do most of the I/O to/from the reader.

Thanks. It's tragic if this chip's cheapness is causing the problem.

BTW, it hasn't been my experience that accessing one PCI device necessarily blocks all access to other PCI devices unless they share an interrupt. Otherwise you could never use 2 PCI devices at the same time in systems.

Only one device can use the PCI bus at any given time. If the System (Chipset or BIOS?) allows one device to occupy it too long other devices no longer work the way they are supposed to. Like audio not getting data from CPU or RAM.

A better BIOS/interrupt handling might, just might, solve the problem.

A faster controller chip would need less time to transfer data, occupying the bus for a shorter period of time.

DVormann wrote:The SD card reader ist connected via PCI. IBM/Lenovo choose to use a very cheap controller chip. Accessing the reader blocks access to all other PCI devices like audio. On top of that, the CPU has to do most of the I/O to/from the reader.

Did Lenovo use a better controller in later laptops?

I was using that SpeedBoost feature with my SD Card. Now that I removed the card, I think my laptop runs faster. Most likely because of this apparent PCI bus contention.