之前给我的MBP (MD101, mid 2012) 换了一个英睿达(Crucial) M500 240G SSD，换上以后用了大约4个多月，并没有任何问题，工作正常。但是最近突然变得速度超级慢完全无法接受，大部分时间 <50iops，偶尔会有一闪而过的 200iops，读写速度基本上是 300kB/s ~ 5MB/s

从正常，到出问题，没有任何我能想到的原因，都是日常那些操作，休眠了一晚上，第二天用的时候就卡的不成样子了。

尝试过的方法如下
* 重置 NVRAM，重置SMC （无效）
* 检查 SMART 数据，健康得很，没有重映射，温度不高，没错误（具体数据附在最后）
* console中没有任何错误日志
* SSD 固件是 MU05，最新版本
* 尝试从Recovery启动，或者从usb启动OS X Installer，发现SSD还是慢的难以忍受（本来是想重装系统，结果发现在Installer下磁盘速度依然有问题，所以觉得这个应该不是OS造成的）
* SSD拿出来放到一个USB3盒子中引导电脑，SATA盘位放上旧的HDD，发现 1. SSD在USB3下工作正常，速度飞快。 2. HDD 速度也正常。。。完全不是那个残废性能（SSD应该没问题，SATA接口应该也没问题。。。）
* 把SSD再放回去发现还是残废性能
* SSD@SATA，光盘启动Ubuntu Live CD发现性能没问题。重启尝试进OS X，又出问题了。（我已经完全搞不懂这是什么问题了。。。。。。。）
* 下载了MU05固件，想刷一下固件，启动后刷新工具提示版本已经最新，无法刷新，但是重启以后，居然SSD性能恢复了
* 好景不长，过了两天以后又残废了，而且这次尝试刷固件没用了。。。

现在就是SSD只要拿出来插usb3盒子，就没问题；插到SATA上就残废性能。。。有没有同样在MBP上使用M500并且时间超过4个月的？能说说是否有问题吗？

----SMART 数据----

location: /dev/disk0
partition count: 0
SMART Support: Supported
Last SMART Error: not set
Model Family: not set
Model: Crucial_CT240M500SSD1
Serial Number: 1427********
Firmware Version: MU05
Capacity: 240 GB
ATA Version: 2
SATA Version: SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
Rotation Rate: Solid State Device
Health: Passed
Overall Health: PASSED
Offline Data Status: 80
Self Test Status: 0
Offline Data Collection Time: 1115
Data Collection Capabilities: 7B
SMART Capabilities: 3
Error Logging Capabilities: 1
Short Self Test Time: 2
Long Self Test Time: 18
Conveyance Self Test Time: 3
Attribute Log Revision: 16
Attribute Count: 23
Attributes:
ID# ATTRIBUTE NAME FLAG VALUE WORST THRESH TYPE UPDATED FAILED RAW VALUE
1 Raw Read Error Rate 0x002F 100 100 000 Pre-fail Always Never 0
5 Reallocated Sector Count 0x0033 100 100 000 Pre-fail Always Never 0
9 Power On Hours 0x0032 100 100 000 Old age Always Never 759
12 Power Cycle Count 0x0032 100 100 000 Old age Always Never 722
171 Unknown Attribute 0x0032 100 100 000 Old age Always Never 0
172 Unknown Attribute 0x0032 100 100 000 Old age Always Never 0
173 Unknown Attribute 0x0032 100 100 000 Old age Always Never 9
174 Unknown Attribute 0x0032 100 100 000 Old age Always Never 16
180 Unused Reserved Block Count Total 0x0033 000 000 000 Pre-fail Always Never 4066
183 Runtime Bad Blocks 0x0032 100 100 000 Old age Always Never 0
184 End-to-End Errors 0x0032 100 100 000 Old age Always Never 0
187 Reported Uncorrectable Errors 0x0032 100 100 000 Old age Always Never 0
194 Temperature Celsius 0x0022 070 051 000 Old age Always Never 30
196 Reallocated Event Count 0x0032 100 100 000 Old age Always Never 0
197 Current Pending Sector Count 0x0032 100 100 000 Old age Always Never 0
198 Offline Uncorrectable Sector Count 0x0030 100 100 000 Old age Offline Never 0
199 UDMA CRC Error Count 0x0032 100 100 000 Old age Always Never 0
202 Unknown SSD Attribute 0x0031 100 100 000 Pre-fail Offline Never 0
206 Unknown SSD Attribute 0x000E 100 100 000 Old age Always Never 0
210 Unknown Attribute 0x0032 100 100 000 Old age Always Never 0
246 Unknown Attribute 0x0032 100 100 000 --- Old age -3500844881
247 Unknown Attribute 0x0032 100 100 000 --- Old age -110022034
248 Unknown Attribute 0x0032 100 100 000 --- Old age -47301207
Error Log Version: 1
Error Count: 0
Error Log:
No errors logged.
Self Test Log Revision: 1
Self Test Log Count: 3
Self Test Log:
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error

1 Vendor (0xff) Completed without error 0% 746 -

2 Vendor (0xff) Completed without error 0% 743 -

3 Short offline Completed without error 0% 738 -

MacBook Pro 与 M500 是否有兼容性问题？有人碰到过严重掉速吗？

1 Vendor (0xff) Completed without error 0% 746 -

2 Vendor (0xff) Completed without error 0% 743 -

3 Short offline Completed without error 0% 738 -